readtable
Create table from file
Syntax
Description
creates a table by reading column-oriented data from a text file, spreadsheet (including
Microsoft®
Excel®) file, XML file, HTML file, or a Microsoft Word document. T
= readtable(filename
)readtable
detects elements of your data, such as
delimiter and data types, to determine how to import your data.
specifies options using one or more name-value arguments. For example, you can read the first
row of the file as variable names or as data by using the T
= readtable(filename
,Name,Value
)ReadVariableNames
name-value argument.
creates a table using the options specified by the import options object
T
= readtable(filename
,opts
)opts
. Use an import options object to configure how
readtable
interprets your file. Compared to name-value arguments, an import
options object provides more control, better performance, and reusability of the file import
configuration.
creates a table using both an import options object and name-value arguments. If you specify
name-value arguments in addition to an import options object, then T
= readtable(filename
,opts
,Name,Value
)readtable
supports only the ReadVariableNames
, ReadRowNames
,
DateLocale
, and Encoding
name-value arguments for text
files, and the ReadVariableNames
, ReadRowNames
,
Sheet
, and UseExcel
name-value arguments for spreadsheet
files.
Examples
Read Text File as Table
Import the contents of a text file into a table. The resulting table contains one variable for each column in the file and uses the entries in the first line of the file as variable names.
T = readtable("myCsvTable.dat")
T=5×6 table
LastName Gender Age Height Weight Smoker
____________ ______ ___ ______ ______ ______
{'Smith' } {'M'} 38 71 176 1
{'Johnson' } {'M'} 43 69 163 0
{'Williams'} {'F'} 38 64 131 0
{'Jones' } {'F'} 40 67 133 0
{'Brown' } {'F'} 49 64 119 0
Read Text File with Missing Data
Create a table from a text file that contains data gaps. By default, readtable
fills the gaps with the appropriate missing values.
T = readtable("headersAndMissing.txt")
T=5×6 table
LastName Gender Age Height Weight Smoker
___________ __________ ___ ______ ______ ______
{'Wu' } {'M' } 38 71 176 1
{'Johnson'} {'M' } 43 69 163 0
{'Sanchez'} {'F' } 38 64 131 0
{'Brown' } {'F' } NaN 67 133 0
{'Picard' } {0x0 char} NaN 64 119 0
To omit the rows with the data gaps, specify the MissingRule
name-value argument.
T = readtable("headersAndMissing.txt",MissingRule="omitrow")
T=3×6 table
LastName Gender Age Height Weight Smoker
___________ ______ ___ ______ ______ ______
{'Wu' } {'M'} 38 71 176 1
{'Johnson'} {'M'} 43 69 163 0
{'Sanchez'} {'F'} 38 64 131 0
Read Subset of Text File Using Import Options
Configure how readtable
interprets your file using an import options object. For example, use an import options object to read only a subset of a text file.
First, create an import options object by using detectImportOptions
to detect aspects of your text file, including variable names and types, delimiters, and white-space characters. In this case, detectImportOptions
creates a DelimitedTextImportOptions
object.
opts = detectImportOptions("airlinesmall.csv")
opts = DelimitedTextImportOptions with properties: Format Properties: Delimiter: {','} Whitespace: '\b\t ' LineEnding: {'\n' '\r' '\r\n'} CommentStyle: {} ConsecutiveDelimitersRule: 'split' LeadingDelimitersRule: 'keep' TrailingDelimitersRule: 'ignore' EmptyLineRule: 'skip' Encoding: 'ISO-8859-1' Replacement Properties: MissingRule: 'fill' ImportErrorRule: 'fill' ExtraColumnsRule: 'addvars' Variable Import Properties: Set types by name using setvartype VariableNames: {'Year', 'Month', 'DayofMonth' ... and 26 more} VariableTypes: {'double', 'double', 'double' ... and 26 more} SelectedVariableNames: {'Year', 'Month', 'DayofMonth' ... and 26 more} VariableOptions: [1-by-29 matlab.io.VariableImportOptions] Access VariableOptions sub-properties using setvaropts/getvaropts VariableNamingRule: 'modify' Location Properties: DataLines: [2 Inf] VariableNamesLine: 1 RowNamesColumn: 0 VariableUnitsLine: 0 VariableDescriptionsLine: 0 To display a preview of the table, use preview
Specify the subset of variables to import by modifying the import options object. Then, import the subset of data using readtable
with the import options object.
opts.SelectedVariableNames = ["TaxiIn","TaxiOut"]; T = readtable("airlinesmall.csv",opts);
Read Spreadsheet File as Table with Row Names
Create a table from a spreadsheet that contains variable names in the first row and row names in the first column. Display the first five rows and first four variables of the table.
T = readtable("patients.xls",ReadRowNames=true);
T(1:5,1:4)
ans=5×4 table
Gender Age Location Height
__________ ___ _____________________________ ______
Smith {'Male' } 38 {'County General Hospital' } 71
Johnson {'Male' } 43 {'VA Hospital' } 69
Williams {'Female'} 38 {'St. Mary's Medical Center'} 64
Jones {'Female'} 40 {'VA Hospital' } 67
Brown {'Female'} 49 {'County General Hospital' } 64
Read Spreadsheet File Using Specific Range
Create a table using data from a specified region of a spreadsheet. Use the data from the 5-by-3 rectangular region between the corners C2
and E6
. Do not use the first row of this region as variable names. The resulting table uses the default variable names instead.
T = readtable("patients.xls",Range="C2:E6",ReadVariableNames=false)
T=5×3 table
Var1 Var2 Var3
____ _____________________________ ____
38 {'County General Hospital' } 71
43 {'VA Hospital' } 69
38 {'St. Mary's Medical Center'} 64
40 {'VA Hospital' } 67
49 {'County General Hospital' } 64
Read Spreadsheet File Using Import Options
Configure how readtable interprets your file using an import options object. For example, use an import options object to read only specified variables from a spreadsheet file.
First, create an import options object from a file by using detectImportOptions
to detect aspects of your spreadsheet file, including variable names and types. In this case, detectImportOptions
creates a SpreadsheetImportOptions
object.
opts = detectImportOptions("patients.xls")
opts = SpreadsheetImportOptions with properties: Sheet Properties: Sheet: '' Replacement Properties: MissingRule: 'fill' ImportErrorRule: 'fill' MergedCellColumnRule: 'placeleft' MergedCellRowRule: 'placetop' Variable Import Properties: Set types by name using setvartype VariableNames: {'LastName', 'Gender', 'Age' ... and 7 more} VariableTypes: {'char', 'char', 'double' ... and 7 more} SelectedVariableNames: {'LastName', 'Gender', 'Age' ... and 7 more} VariableOptions: [1-by-10 matlab.io.VariableImportOptions] Access VariableOptions sub-properties using setvaropts/getvaropts VariableNamingRule: 'modify' Range Properties: DataRange: 'A2' (Start Cell) VariableNamesRange: 'A1' RowNamesRange: '' VariableUnitsRange: '' VariableDescriptionsRange: '' To display a preview of the table, use preview
Specify which variables to import by modifying the import options object. Then, import the specified variables using readtable
with the import options object. Display the first 5 rows of the table.
opts.SelectedVariableNames = ["Systolic","Diastolic"]; T = readtable("patients.xls",opts); T(1:5,:)
ans=5×2 table
Systolic Diastolic
________ _________
124 93
109 77
125 83
117 75
122 80
Read XML File as Table
Import the contents of an XML file into a table.
The students.xml
file has seven sibling nodes named Student
, which each contain the same child nodes and attributes.
type students.xml
<?xml version="1.0" encoding="utf-8"?> <Students> <Student ID="S11305"> <Name FirstName="Priya" LastName="Thompson" /> <Age>18</Age> <Year>Freshman</Year> <Address> <Street xmlns="https://www.mathworks.com">591 Spring Lane</Street> <City>Natick</City> <State>MA</State> </Address> <Major>Computer Science</Major> <Minor>English Literature</Minor> </Student> <Student ID="S23451"> <Name FirstName="Conor" LastName="Cole" /> <Age>18</Age> <Year>Freshman</Year> <Address> <Street xmlns="https://www.mathworks.com">4641 Pearl Street</Street> <City>San Francisco</City> <State>CA</State> </Address> <Major>Microbiology</Major> <Minor>Public Health</Minor> </Student> <Student ID="S119323"> <Name FirstName="Morgan" LastName="Yang" /> <Age>21</Age> <Year>Senior</Year> <Address> <Street xmlns="https://www.mathworks.com">30 Highland Road</Street> <City>Detriot</City> <State>MI</State> </Address> <Major>Political Science</Major> </Student> <Student ID="S201351"> <Name FirstName="Salim" LastName="Copeland" /> <Age>19</Age> <Year>Sophomore</Year> <Address> <Street xmlns="https://www.mathworks.com">3388 Moore Avenue</Street> <City>Fort Worth</City> <State>TX</State> </Address> <Major>Business</Major> <Minor>Japanese Language</Minor> </Student> <Student ID="S201351"> <Name FirstName="Salim" LastName="Copeland" /> <Age>20</Age> <Year>Sophomore</Year> <Address> <Street xmlns="https://www.mathworks.com">3388 Moore Avenue</Street> <City>Fort Worth</City> <State>TX</State> </Address> <Major>Business</Major> <Minor>Japanese Language</Minor> </Student> <Student ID="54600"> <Name FirstName="Dania" LastName="Burt" /> <Age>22</Age> <Year>Senior</Year> <Address> <Street xmlns="https://www.mathworks.com">22 Angie Drive</Street> <City>Los Angeles</City> <State>CA</State> </Address> <Major>Mechanical Engineering</Major> <Minor>Architecture</Minor> </Student> <Student ID="453197"> <Name FirstName="Rikki" LastName="Gunn" /> <Age>21</Age> <Year>Junior</Year> <Address> <Street xmlns="https://www.mathworks.com">65 Decatur Lane</Street> <City>Trenton</City> <State>ME</State> </Address> <Major>Economics</Major> <Minor>Art History</Minor> </Student> </Students>
First, create an XMLImportOptions
object by using detectImportOptions
to detect aspects of your XML file. Read just the street names into a table by specifying the VariableSelectors
name-value argument as the XPath expression of the Street
element node. Register a custom namespace prefix to the existing namespace URL by setting the RegisteredNamespaces
name-value argument.
opts = detectImportOptions("students.xml",RegisteredNamespaces=["myPrefix","https://www.mathworks.com"], ... VariableSelectors="//myPrefix:Street");
Then, import the specified variable using readtable
with the import options object.
T = readtable("students.xml",opts)
T=7×1 table
Street
___________________
"591 Spring Lane"
"4641 Pearl Street"
"30 Highland Road"
"3388 Moore Avenue"
"3388 Moore Avenue"
"22 Angie Drive"
"65 Decatur Lane"
Read Microsoft Word Document as Table
Import a table from a Microsoft Word document into a table in MATLAB. In this case, the document contains two tables, and the second table contains merged cells. Read the second table by setting the TableIndex
name-value argument. Skip rows that have cells with merged columns by setting the MergedCellColumnRule
name-value argument.
filename = "MaintenanceReport.docx"; T = readtable(filename,TableIndex=2,MergedCellColumnRule="omitrow")
T=3×5 table
Description Category Urgency Resolution Cost
_____________________________________________________________________ ____________________ ________ __________________ ________
"Items are occasionally getting stuck in the scanner spools." "Mechanical Failure" "Medium" "Readjust Machine" "$45"
"Loud rattling and banging sounds are coming from assembler pistons." "Mechanical Failure" "Medium" "Readjust Machine" "$35"
"There are cuts to the power when starting the plant." "Electronic Failure" "High" "Full Replacement" "$16200"
Alternatively, you can select a table with an XPath selector by using the TableSelector
name-value argument. To select the Microsoft Word document table that contains the text "Description", use the XPath selector "//w:tbl[contains(.,'Description')]"
.
T = readtable(filename, ... TableSelector="//w:tbl[contains(.,'Description')]", ... MergedCellColumnRule="omitrow")
T=3×5 table
Description Category Urgency Resolution Cost
_____________________________________________________________________ ____________________ ________ __________________ ________
"Items are occasionally getting stuck in the scanner spools." "Mechanical Failure" "Medium" "Readjust Machine" "$45"
"Loud rattling and banging sounds are coming from assembler pistons." "Mechanical Failure" "Medium" "Readjust Machine" "$35"
"There are cuts to the power when starting the plant." "Electronic Failure" "High" "Full Replacement" "$16200"
Read HTML Webpage as Table
Import the first table from the URL https://www.mathworks.com/help/matlab/text-files.html
that contains the text "readtable"
using the XPath selector "//TABLE[contains(.,'readtable')]"
. The table does not have a header row, so set the ReadVariableNames
name-value argument to false
.
url = "https://www.mathworks.com/help/matlab/text-files.html"; T = readtable(url,TableSelector="//TABLE[contains(.,'readtable')]", ... ReadVariableNames=false)
T=4×2 table
Var1 Var2
________________ ____________________________
"readtable" "Create table from file"
"writetable" "Write table to file"
"readtimetable" "Create timetable from file"
"writetimetable" "Write timetable to file"
Input Arguments
filename
— Name of file to read
string scalar | character vector
Name of the file to read, specified as a string scalar or character vector.
readtable
supports reading data from text, spreadsheet, XML, and HTML
files as well as Microsoft Word documents.
If filename
does not include an extension, use the
FileType
name-value argument to indicate the file format. By default,
readtable
creates variables that have data types that are appropriate for
the data values detected in each column of the input file.
Depending on the location of your file, filename
can take on one of
these forms.
Location | Form | ||||||||
---|---|---|---|---|---|---|---|---|---|
Current folder or folder on the MATLAB® path | Specify the name of the file in
Example:
| ||||||||
File in a folder | If the file is not in the current folder or in a folder on the MATLAB path, then specify the full or relative pathname in
Example:
Example:
| ||||||||
Internet URL | If the file is specified as an internet uniform resource locator (URL), then
Example:
| ||||||||
Remote Location | If the file is stored at a remote location, then
Based on the remote location,
For more information, see Work with Remote Data. Example: Example: Example: |
Text Files
Files with
.txt
,.dat
, or.csv
extensions are read as delimited text files.By default,
readtable
creates one table variable for each column in the file and reads variable names from the first row of the file. Empty fields are converted to eitherNaN
for a numeric variable or an empty character vector for a text variable. White space is ignored when reading the file.All lines in the text file must have the same number of delimiters.
For more options, see the name value arguments for Text Files.
For commonly used text file workflows, see Import Data from Text File to Table.
Spreadsheet Files
Files with
.xls
,.xlsb
,.xlsm
,.xlsx
,.xltm
,.xltx
, or.ods
extensions are read as spreadsheet files.By default,
readtable
creates one table variable for each column in the file and reads variable names from the first row of the file.On Windows® systems with Microsoft Excel software,
readtable
reads any Excel spreadsheet file format recognized by your version of Excel. If your system does not have Microsoft Excel for Windows or if you are using MATLAB Online™, thenreadtable
operates with theUseExcel
property set tofalse
and reads only files with.xls
,.xlsm
,.xlsx
,.xltm
, and.xltx
extensions.Large files in XLSX format sometimes load slowly. For better import and export performance, Microsoft recommends that you use the XLSB format.
For more options, see the name value arguments for Spreadsheet Files.
For commonly used spreadsheet file workflows, see Read Spreadsheet Data into Table.
XML Files
Files with the
.xml
extension are read as Extensible Markup Language (XML) files.By default,
readtable
creates one table variable for each element or attribute node detected as a table variable. Variable names correspond to element and attribute names.
For more options, see the name value arguments for XML Files.
Microsoft Word Document Files
Files with the
.docx
extension are read as Microsoft Word document files.By default,
readtable
imports data from the first table in the document, creates one table variable for each column in the file, and reads variable names from the first row of the table.
For more options, see the name value arguments for Microsoft Word Document Files.
HTML Files
Files with the
.html
,.xhtml
, or.htm
extensions are read as Hypertext Markup Language (HTML) files.By default,
readtable
imports data from the first<TABLE>
element, creates one table variable for each column in the file, and reads variable names from the first row of the table.
For more options, see the name value arguments for HTML Files.
opts
— File import options
DelimitedTextImportOptions
object | FixedWidthImportOptions
object | SpreadsheetImportOptions
object | …
File import options, specified as one of the import options objects in the table, created
by either the detectImportOptions
function or the associated import options
function. The import options object contains properties that configure the data import
process. readtable
uses only the relevant properties of each import options
object.
File Type | Import Options Object |
---|---|
Text files | DelimitedTextImportOptions object |
Fixed-width text files | FixedWidthImportOptions object |
Spreadsheet files | SpreadsheetImportOptions object |
XML files | XMLImportOptions
object |
Microsoft Word document | WordDocumentImportOptions object |
HTML files | HTMLImportOptions object |
For more information on how to control your import, see Control How MATLAB Imports Your Data.
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Example: readtable(filename,ReadVariableNames=false)
indicates that the
first row of the file does not correspond to variable names.
Before R2021a, use commas to separate each name and value, and enclose
Name
in quotes.
Example: readtable(filename,"ReadVariableNames",false)
indicates that the
first row of the file does not correspond to variable names.
FileType
— Type of file
"spreadsheet"
| "text"
| "delimitedtext"
| "fixedwidth"
| "xml"
| "worddocument"
| "html"
Type of file, specified as one of these values.
Value | File Type |
---|---|
"spreadsheet" | Spreadsheet files |
"text" | Text files |
"delimitedtext" | Delimited text files |
"fixedwidth" | Fixed-width text files |
"xml" | XML files |
"worddocument" | Microsoft Word document |
"html" | HTML files |
Use the "FileType"
name-value pair argument when
filename
does not include the file extension, or when the extension is
not one of these:
.txt
,.dat
, or.csv
for text files.xls
,.xlsb
,.xlsm
,.xlsx
,.xltm
,.xltx
, or.ods
for spreadsheet files.xml
, for XML files.docx
for Microsoft Word document files.html
,.xhtml
, or.htm
for HTML files
Example: "FileType","text"
ReadRowNames
— Option to read first column as row names
false
or 0
(default) | true
or 1
Option to read the first column as row names, specified as a numeric or logical 1 (true) or 0 (false).
Set
ReadRowNames
totrue
when the first column of the region to read contains the row names for the table.Set
ReadRowNames
tofalse
when the first column of the region to read contains data, not the row names for the table.
If both the ReadVariableNames
and ReadRowNames
name-value arguments are true
, then readtable
saves the
name in the first column of the first row of the region to read as the first dimension name
in the property T.Properties.DimensionNames
.
If you specify the ReadRowNames
argument in addition to an import
options object, then the readtable
behavior changes based on the specification:
If
ReadRowNames
istrue
, then read the row names from the specified file by using theRowNamesColumn
(DelimitedTextImportOptions
,FixedWidthImportOptions
),RowNamesRange
(SpreadsheetImportOptions
), orRowNamesSelector
(XMLImportOptions
) property of the respective import options object.If
ReadRowNames
isfalse
, then do not import row names.
If you use the import options syntax without specifying ReadRowNames
,
readtable
uses the value associated with the import options object and
its ReadRowNames
name-value argument.
Example: "ReadRowNames",true
Delimiter
— Field delimiter character
character vector | cell array of character vectors | string
Field delimiter character, specified as Delimiter
and a character
vector, a cell array of character vectors, or a string. Specify Delimiter
using any valid character such as a comma ","
or a period
"."
.
This table lists some commonly used field delimiter characters.
Specifier | Field Delimiter |
---|---|
| Comma |
| Space |
| Tab |
| Semicolon |
| Vertical bar |
unspecified | If unspecified, |
To treat consecutive delimiters as a single delimiter, specify
Delimiter
as a cell array of character vectors. In addition, you must
also specify the MultipleDelimsAsOne
option.
Example: "Delimiter",","
or
"Delimiter","comma"
LeadingDelimitersRule
— Procedure to manage leading delimiters
"keep"
| "ignore"
| "error"
Procedure to manage leading delimiters in a delimited text file, specified as one of the values in this table.
Leading Delimiters Rule | Behavior |
---|---|
"keep" | Keep the delimiter. |
"ignore" | Ignore the delimiter. |
"error" | Return an error and abort the import operation. |
Example: "LeadingDelimitersRule","keep"
TrailingDelimitersRule
— Procedure to manage trailing delimiters
"keep"
| "ignore"
| "error"
Procedure to manage trailing delimiters in a delimited text file, specified as one of the values in this table.
Trailing Delimiters Rule | Behavior |
---|---|
"keep" | Keep the delimiter. |
"ignore" | Ignore the delimiter. |
"error" | Return an error and abort the import operation. |
Example: "TrailingDelimitersRule","keep"
ConsecutiveDelimitersRule
— Procedure to handle consecutive delimiters
"split"
| "join"
| "error"
Procedure to handle consecutive delimiters in a delimited text file, specified as one of the values in this table.
Consecutive Delimiters Rule | Behavior |
---|---|
"split" | Split the consecutive delimiters into multiple fields. |
"join" | Join the delimiters into one delimiter. |
"error" | Return an error and abort the import operation. |
Example: "ConsecutiveDelimitersRule","split"
MultipleDelimsAsOne
— Multiple delimiter handling
0 (false)
(default) | 1 (true)
Multiple delimiter handling, specified as MultipleDelimsAsOne
and
either true
or false
. If true
, then
readtable
treats consecutive delimiters as a single delimiter. Repeated
delimiters separated by white-space are also treated as a single delimiter. You must also
specify the Delimiter
option.
Example: "MultipleDelimsAsOne",1
NumHeaderLines
— Number of header lines
0
| positive integer
Number of header lines to skip at the beginning of the file, specified as
NumHeaderLines
and either 0
or a positive integer. If
unspecified, readtable
automatically detects the number of lines to
skip.
Example: "NumHeaderLines",2
Data Types: single
| double
TreatAsMissing
— Placeholder text to treat as empty value
character vector | cell array of character vectors | string scalar | string array
Placeholder text to treat as an empty value, specified as
"TreatAsMissing"
and a character vector, cell array of character vectors,
string scalar, or string array. Table elements corresponding to these characters are set to
the missing value associated with the data type. For more information, see fillmissing
.
Example: "TreatAsMissing","N/A"
or
"TreatAsMissing","N/A"
sets N/A
within numeric columns
to NaN
.
Example: "TreatAsMissing",{'.','NA','N/A'}
or
"TreatAsMissing",[".","NA","N/A"]
sets .
,
NA
and N/A
within numeric columns to
NaN
.
MissingRule
— Procedure to manage missing data
"fill"
(default) | "error"
| "omitrow"
| "omitvar"
Procedure to manage missing data, specified as one of the values in this table. Data is considered missing if an expected field in a row does not exist. Because missing fields cause subsequent elements of a row to shift fields, the missing fields are interpreted at the end of the row.
Missing Rule | Behavior |
---|---|
"fill" | Replace missing data with the contents of the The |
"error" | Stop importing and display an error message showing the missing record and field. |
"omitrow" | Omit rows that contain missing data. |
"omitvar" | Omit variables that contain missing data. |
Example: "MissingRule","omitrow"
TextType
— Type for imported text data
"string"
| "char"
Type for imported text data, specified as one of these values:
"string"
— Import text data as string arrays."char"
— Import text data as character vectors.
Example: "TextType","char"
DatetimeType
— Type for imported date and time data
"datetime"
(default) | "text"
| "exceldatenum"
(spreadsheet files only)
Type for imported date and time data, specified as DatetimeType
and
one of these values: "datetime"
, "text"
, or
"exceldatenum"
. The value "exceldatenum"
is applicable
only for spreadsheet files, and is not valid for text files.
Value | Type for Imported Date and Time Data |
---|---|
"datetime" | MATLAB
For more information, see |
"text" | If
|
"exceldatenum"
| Excel serial date numbers A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see Differences between the 1900 and the 1904 date system in Excel. |
Example: "DatetimeType","datetime"
VariableNamingRule
— Flag to preserve variable names
"modify"
(default) | "preserve"
Flag to preserve variable names, specified as either "modify"
or
"preserve"
.
"modify"
— Convert invalid variable names (as determined by theisvarname
function) to valid MATLAB identifiers."preserve"
— Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.
Starting in R2019b, variable names and row names can include any characters, including
spaces and non-ASCII characters. Also, they can start with any characters, not just letters.
Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname
function). To preserve these variable names and row names, set the
value of VariableNamingRule
to "preserve"
. Variable
names are not refreshed when the value of VariableNamingRule
is changed
from "modify"
to "preserve"
.
Example: "VariableNamingRule","preserve"
ImportErrorRule
— Procedure to handle import errors
"fill"
(default) | "error"
| "omitrow"
| "omitvar"
Procedure to handle import errors, specified as one of the values in this table. An
import error occurs when readtable
is unable to convert a text element to
the expected data type.
Import Error Rule | Behavior |
---|---|
"fill" | Replace the data where the error occurred with the contents of the
The |
"error" | Stop importing and display an error message showing the error-causing record and field. |
"omitrow" | Omit rows where errors occur. |
"omitvar" | Omit variables where errors occur. |
Example: "ImportErrorRule","omitvar"
WebOptions
— HTTP
or HTTPS
request options
weboptions
object
HTTP
or HTTPS
request options, specified as a
weboptions
object. The weboptions
object determines how to
import data when the specified filename
is an internet URL containing the
protocol type "http://"
or "https://"
.
ReadVariableNames
— Read first row as variable names
true
| false
| 1
| 0
Indicator for reading the first row as variable names, specified as
ReadVariableNames
and either true
,
false
, 1
, or 0
. If unspecified,
readtable
automatically detects the presence of variable
names.
Indicator | Description |
---|---|
| Use when the first row of the region to read contains the variable names for
the table. |
| Use when the first row of the region to read contains data in the table.
|
unspecified | When left unspecified, readtable automatically detects
true or false and proceeds accordingly. |
Note: If both the
"ReadVariableNames"
and "ReadRowNames"
logical
indicators are true
, then readtable
saves the name in
the first column of the first row of the region to read as the first dimension name in the
property, T.Properties.DimensionNames
.
If you specify the ReadVariableNames
argument in addition to
opts
the import options, then the readtable
behavior
changes based on the specification:
If
ReadVariableNames
istrue
, then read the variable names from the specified file by using theVariableNamesRange
or theVariableNamesLine
property of the import options object.If
ReadVariableNames
isfalse
, then read the variable names from theVariableNames
property of the import options object.
Example: "ReadVariableNames",true
ExpectedNumVariables
— Expected number of variables
positive integer
Expected number of variables, specified as ExpectedNumVariables
and a
positive integer. If unspecified, readtable
automatically detects the
number of variables.
Example: "ExpectedNumVariables",5
Data Types: single
| double
VariableWidths
— Field widths of variables
vector of positive integer values
Field widths of variables in a fixed-width text file, specified as a vector of positive
integer values. Each positive integer in the vector corresponds to the number of characters
in a field that makes up the variable. The VariableWidths
property
contains an entry corresponding to each variable specified in the
VariableNames
property.
Example: "VariableWidths",[10,7,4,26,7]
Whitespace
— Characters to treat as white space
string scalar | character vector
Characters to treat as white space, specified as a string scalar or character vector containing one or more characters.
This table shows how to represent special characters that you cannot enter using ordinary text.
Special Character | Representation |
---|---|
Percent character |
|
Backslash |
|
Alarm |
|
Backspace |
|
Form feed |
|
New line |
|
Carriage return |
|
Horizontal tab |
|
Vertical tab |
|
Character whose Unicode® numeric value can be represented by the hexadecimal number,
|
|
Character whose Unicode numeric value can be represented by the octal number,
|
|
Example: "Whitespace"," _"
Example: "Whitespace","?!.,"
EmptyLineRule
— Procedure to handle empty lines
"skip"
| "read"
| "error"
Procedure to handle empty lines in the data, specified as one of the values in this
table. readtable
interprets white space as empty. A line is considered
empty if it contains no fields. A line is defined by two end-of-line characters.
Empty Line Rule | Behavior |
---|---|
"skip" | Skip the empty lines. |
"read" | Import the empty lines. readtable parses an empty line using the
values specified in VariableWidths ,
VariableOptions , MissingRule , and other relevant
properties, such as Whitespace . |
"error" | Display an error message and cancel the import operation. |
Example: "EmptyLineRule","skip"
VariableNamesLine
— Variable names location
0
(default) | positive scalar integer
Variable names location, specified as a positive scalar integer. The
VariableNamesLine
property specifies the line number where variable names
are located.
If VariableNamesLine
is specified as 0, then do not import the
variable names. Otherwise, import the variable names from the specified line.
Example: "VariableNamesLine",6
Data Types: single
| double
| uint8
| uint16
| uint32
| uint64
PartialFieldRule
— Procedure to handle partial fields
"keep"
| "fill"
| "omitrow"
| "omitvar"
| "wrap"
| "error"
Procedure to handle partial fields in the data, specified as one of the values in this table. A field is considered partially filled if it terminates before the end of the expected width. This applies only to fields with fixed widths.
Partial Field Rule | Behavior |
---|---|
"keep" | Keep the partial field data and convert the text to the appropriate data type. In some cases, when |
"fill" | Replace missing data with the contents of the The |
"omitrow" | Omit rows that contain partial data. |
"omitvar" | Omit variables that contain partial data. |
"wrap" | Begin reading the next line of characters. |
"error" | Display an error message and cancel the import operation. |
Example: "PartialFieldRule","keep"
VariableUnitsLine
— Variable units location
0
(default) | positive scalar integer
Variable units location, specified as a positive scalar integer. The
VariableUnitsLine
property specifies the line number where variable units
are located.
If VariableUnitsLine
is specified as 0, then do not import the
variable units. Otherwise, import the variable units from the specified line.
Example: "VariableUnitsLine",8
Data Types: single
| double
| uint8
| uint16
| uint32
| uint64
VariableDescriptionsLine
— Variable description location
0
(default) | positive scalar integer
Variable description location, specified as a positive scalar integer. The
VariableDescriptionsLine
property specifies the line number where
variable descriptions are located.
If VariableDescriptionsLine
is specified as 0, then do not import the
variable descriptions. Otherwise, import the variable descriptions from the specified
line.
Example: "VariableDescriptionsLine",7
Data Types: single
| double
| uint8
| uint16
| uint32
| uint64
ExtraColumnsRule
— Procedure to handle extra columns
"addvars"
| "ignore"
| "wrap"
| "error"
Procedure to handle extra columns in the data, specified as one of the values in this table. Columns are considered extra if a row has more columns than expected.
Extra Columns Rule | Behavior |
---|---|
"addvars" | To import extra columns, create new variables. If there are
The extra
columns are imported as text with data type |
"ignore" | Ignore the extra columns of data. |
"wrap" | Wrap the extra columns of data to new records. This action does not change the number of variables. |
"error" | Display an error message and cancel the import operation. |
Example: "ExtraColumnsRule","addvars"
Format
— Column format
character vector | string scalar | "auto"
Column format of the file, specified as Format
and a character vector
or a string scalar having one or more conversion specifiers, or "auto"
.
The conversion specifiers are the same as the specifiers accepted by the
textscan
function.
Specifying the format can significantly improve speed for some large files. If you do
not specify a value for Format
, then readtable
uses
%q
to interpret nonnumeric columns. The %q
specifier
reads the text and omits double quotation marks ("
) if appropriate.
If you do not specify the
"Format"
name-value pair, then thereadtable
function behaves as though you have used the results of thedetectImportOptions
function to import the data. For more information on the consequences of this behavior, see Compatibility Considerations.If you specify
"Format","auto"
, then the variables created aredouble
arrays, cell array of character vectors, ordatetime
arrays, depending on the data. If the entire column is numeric, variables are imported asdouble
. If any element in a column is not numeric, the variables are imported as cell arrays of character vectors, or asdatetime
arrays if the values represent dates and times.
Example: "Format","auto"
EmptyValue
— Returned value for empty numeric fields
NaN
(default) | numeric scalar
Returned value for empty numeric fields in delimited text files, specified as
EmptyValue
and a numeric scalar.
Example: "EmptyValue",0
CollectOutput
— Logical indicator determining data concatenation
false
(default) | true
Logical indicator determining data concatenation, specified as
CollectOutput
and either true
or
false
. If true
, then readtable
concatenates consecutive output cells of the same fundamental MATLAB class into a single array.
Example: "CollectOutput",true
CommentStyle
— Symbols designating text to ignore
character vector | cell array of character vectors | string scalar | string array
Symbols designating text to ignore, specified as CommentStyle
and a
character vector, cell array of character vectors, string scalar, or string array.
For example, specify a character such as "%"
to ignore text following
the symbol on the same line. Specify a cell array of two character vectors, such as
{'/*','*/'}
, to ignore any text between those sequences.
MATLAB checks for comments only at the start of each field, not within a field.
Example: "CommentStyle",{'/*','*/'}
ExponentCharacter
— Exponent characters
"eEdD"
(default) | character vector | string scalar
Exponent characters, specified as ExponentCharacter
and a character
vector or string scalar. The default exponent characters are e
,
E
, d
, and D
.
Example: "ExponentCharacter","eE"
LineEnding
— End-of-line characters
character vector | string scalar
End-of-line characters, specified as LineEnding
and a character
vector or string scalar. The character vector must be "\r\n"
or it must
specify a single character. Common end-of-line characters are a newline character
("\n"
) or a carriage return ("\r"
). If you specify
"\r\n"
, then readtable
treats any of
\r
, \n
, and the combination of the two
(\r\n
) as end-of-line characters.
The default end-of-line sequence is \n
, \r
, or
\r\n
, depending on the contents of your file.
If there are missing values and an end-of-line sequence at the end of the last line in a
file, then readtable
returns empty values for those fields. This ensures
that individual cells in output cell array, C
, are the same size.
Example: "LineEnding",":"
DateLocale
— Locale for reading dates
character vector | string scalar
Locale for reading dates, specified as DateLocale
and a character
vector or a string scalar of the form
, where:xx
_YY
YY
is an uppercase ISO 3166-1 alpha-2 code indicating a country.xx
is a lowercase ISO 639-1 two-letter code indicating a language.
This table lists some common values for the locale.
Locale | Language | Country |
---|---|---|
"de_DE" | German | Germany |
"en_GB" | English | United Kingdom |
"en_US" | English | United States |
"es_ES" | Spanish | Spain |
"fr_FR" | French | France |
"it_IT" | Italian | Italy |
"ja_JP" | Japanese | Japan |
"ko_KR" | Korean | Korea |
"nl_NL" | Dutch | Netherlands |
"zh_CN" | Chinese (simplified) | China |
When using the %D
format specifier to read text as
datetime
values, use DateLocale
to specify the locale
in which readtable
should interpret month and day-of-week names and
abbreviations.
If you specify the DateLocale
argument in addition to
opts
the import options, then readtable
uses the
specified value for the DateLocale
argument, overriding the locale defined
in the import options.
Example: "DateLocale","ja_JP"
DecimalSeparator
— Characters indicating decimal separator
character vector | string scalar
Characters indicating the decimal separator in numeric variables, specified as a
character vector or string scalar. The readtable
uses the characters
specified in the DecimalSeparator
name-value argument to distinguish the
integer part of a number from the decimal part.
When converting to integer data types, numbers with a decimal part are rounded to the nearest integer.
Example: If name-value pair is specified as "DecimalSeparator",","
,
then readtable
imports the text "3,14159"
as the number
3.14159
.
ThousandsSeparator
— Characters that indicate thousands grouping
character vector | string scalar
Characters that indicate the thousands grouping in numeric variables, specified as a
character vector or string scalar. The thousands grouping characters act as visual
separators, grouping the number at every three place values. The readtable
uses the characters specified in the ThousandsSeparator
name-value
argument to interpret the numbers being imported.
Example: If name-value pair is specified as "ThousandsSeparator",","
,
then readtable
imports the text "1,234,000"
as
1234000
.
TrimNonNumeric
— Remove nonnumeric characters
false
(default) | true
Remove nonnumeric characters from a numeric variable, specified as a logical
true
or false
.
Example: If name-value pair is specified as "TrimNonNumeric",true
,
then readtable
reads "$500/-"
as
500
.
Data Types: logical
Encoding
— Character encoding scheme
"UTF-8"
| "ISO-8859-1"
| "windows-1251"
| "windows-1252"
| ...
Character encoding scheme associated with the file, specified as
Encoding
and "system"
or a standard character encoding
scheme name. When you do not specify any encoding, the readtable
function uses automatic character set detection to determine the encoding when reading the
file.
If you specify the "Encoding"
argument in addition to the import
options, then the readtable
function uses the specified value for
"Encoding"
, overriding the encoding defined in the import options.
Example: "Encoding","UTF-8"
uses UTF-8 as the encoding.
Example: "Encoding","system"
uses the system default
encoding.
DurationType
— Output data type of duration data
"duration"
(default) | "text"
Output data type of duration data from text files, specified as
DurationType
and either "duration"
or
"text"
.
Value | Type for Imported Duration Data |
---|---|
"duration" | MATLAB
For more information, see |
"text" | If
|
Example: "DurationType","text"
HexType
— Output data type of hexadecimal data
"auto"
(default) | "text"
| "int8"
| "int16"
| ...
Output data type of hexadecimal data, specified as HexType
and one of
the values listed in the table.
The input file represents hexadecimal values as text, using either 0x
or 0X
as a prefix and the characters
0
-9
, a
-f
, and
A
-F
as digits. (Uppercase and lowercase letters
represent the same digits—for example, "0xf"
and "0xF"
both represent 15
.)
readtable
converts the hexadecimal values to the data type specified
by the value of "HexType"
.
Value of | Data Type of Output Table Variables |
---|---|
| data type detected automatically |
| unaltered input text |
| 8-bit integer, signed |
| 16-bit integer, signed |
| 32-bit integer, signed |
| 64-bit integer, signed |
| 8-bit integer, unsigned |
| 16-bit integer, unsigned |
| 32-bit integer, unsigned |
| 64-bit integer, unsigned |
Example: "HexType","uint16"
converts text representing hexadecimal
values (such as "0xFF"
) to unsigned 16-bit integers (such as
255
) in the output table.
BinaryType
— Output data type of binary data
"auto"
(default) | "text"
| "int8"
| "int16"
| ...
Output data type of binary data, specified as BinaryType
and one of
the values listed in the table.
The input file represents binary values as text, using either 0b
or
0B
as a prefix and the characters 0
and
1
as digits.
readtable
converts the binary values to the data type specified by
the value of "BinaryType"
.
Value of | Data Type of Output Table Variables |
---|---|
| data type detected automatically |
| unaltered input text |
| 8-bit integer, signed |
| 16-bit integer, signed |
| 32-bit integer, signed |
| 64-bit integer, signed |
| 8-bit integer, unsigned |
| 16-bit integer, unsigned |
| 32-bit integer, unsigned |
| 64-bit integer, unsigned |
Example: "BinaryType","uint16"
converts text representing binary
values (such as "0b11111111"
) to unsigned 16-bit integers (such as
255
) in the output table.
FileType
— Type of file
"spreadsheet"
| "text"
| "delimitedtext"
| "fixedwidth"
| "xml"
| "worddocument"
| "html"
Type of file, specified as one of these values.
Value | File Type |
---|---|
"spreadsheet" | Spreadsheet files |
"text" | Text files |
"delimitedtext" | Delimited text files |
"fixedwidth" | Fixed-width text files |
"xml" | XML files |
"worddocument" | Microsoft Word document |
"html" | HTML files |
Use the "FileType"
name-value pair argument when
filename
does not include the file extension, or when the extension is
not one of these:
.txt
,.dat
, or.csv
for text files.xls
,.xlsb
,.xlsm
,.xlsx
,.xltm
,.xltx
, or.ods
for spreadsheet files.xml
, for XML files.docx
for Microsoft Word document files.html
,.xhtml
, or.htm
for HTML files
Example: "FileType","text"
ReadRowNames
— Option to read first column as row names
false
or 0
(default) | true
or 1
Option to read the first column as row names, specified as a numeric or logical
1
(true
) or 0
(false
).
Set
ReadRowNames
totrue
when the first column of the region to read contains the row names for the table.Set
ReadRowNames
tofalse
when the first column of the region to read contains data, not the row names for the table.
If both the ReadVariableNames
and ReadRowNames
name-value arguments are true
, then readtable
saves the
name in the first column of the first row of the region to read as the first dimension name
in the property, T.Properties.DimensionNames
.
If you specify the ReadRowNames
argument in addition to an import
options object, then the readtable
behavior changes based on the specification:
If
ReadRowNames
istrue
, then read the row names from the specified file by using theRowNamesColumn
(DelimitedTextImportOptions
,FixedWidthImportOptions
),RowNamesRange
(SpreadsheetImportOptions
), orRowNamesSelector
(XMLImportOptions
) property of the respective import options object.If
ReadRowNames
isfalse
, then do not import row names.
If you use the import options syntax without specifying ReadRowNames
,
readtable
uses the value associated with the import options object and
its ReadRowNames
name-value argument.
Example: "ReadRowNames",true
TreatAsMissing
— Placeholder text to treat as empty value
character vector | cell array of character vectors | string scalar | string array
Placeholder text to treat as an empty value, specified as
TreatAsMissing
and a character vector, cell array of character vectors,
string scalar, or string array. Table elements corresponding to these characters are set to
the missing value associated with the data type. For more information, see fillmissing
.
Example: "TreatAsMissing","N/A"
or
"TreatAsMissing","N/A"
sets N/A
within numeric columns
to NaN
.
Example: "TreatAsMissing",{'.','NA','N/A'}
or
"TreatAsMissing",[".","NA","N/A"]
sets .
,
NA
and N/A
within numeric columns to
NaN
.
MissingRule
— Procedure to manage missing data
"fill"
(default) | "error"
| "omitrow"
| "omitvar"
Procedure to manage missing data, specified as one of the values in this table. Data is considered missing if the expected field in the row has no data and the field type is blank or empty.
Missing Rule | Behavior |
---|---|
"fill" | Replace missing data with the contents of the The |
"error" | Stop importing and display an error message showing the missing record and field. |
"omitrow" | Omit rows that contain missing data. |
"omitvar" | Omit variables that contain missing data. |
Example: "MissingRule","omitrow"
Range
— Portion of worksheet to read
character vector | string scalar
Portion of the worksheet to read, indicated as a rectangular area specified as a character vector or string scalar in one of the following forms.
Ways to specify Range
| Description |
---|---|
Starting Cell | Specify the starting cell for the data as a character vector or string scalar or a two element numeric vector.
Using the starting cell, Example:
|
Rectangular Range | Specify the range using the syntax
Example:
|
Unspecified or Empty | If unspecified, Example:
Note:
Used Range refers to the rectangular portion of the spreadsheet
that actually contains data. |
Row Range | You can identify range by specifying the beginning and ending rows using
Excel row designators. Then Example:
|
Column Range | You can identify range by specifying the beginning and ending columns using
Excel column designators. Then Example:
|
Named Range in Excel | In Excel, you can create names to identify ranges in the spreadsheet. For instance,
you can select a rectangular portion of the spreadsheet and call it
Example:
|
Example: "Range"
, "A1:F10"
Example: "Range"
, "A1:F10"
—
DataRange
— Location of data
character vector | string scalar | positive scalar integer | array of positive scalar integers | cell array of character vector | string array
Location of data to be imported, specified as a character vector, string scalar, cell
array of character vectors, string array, positive scalar integer or an
N
-by-2
array of positive scalar integers. Specify
DataRange
using one of these forms.
Specified by | Behavior |
---|---|
Starting Cell or Starting Row | Specify the starting cell for the data, using Excel
Using the starting cell,
Alternatively, specify the first row containing the data using the positive scalar row index. Using the specified row index,
Example:
|
Rectangular Range | Specify the exact range to read using the rectangular range form, where
The number of columns must match the number specified in the
Example:
|
Row Range or Column Range | Specify the range by identifying the beginning and ending rows using Excel row numbers. Using the specified row range,
Example:
Alternatively, specify the range by identifying the beginning and ending columns using Excel column letters or numbers. Using the specified column range, the import function automatically detects the row extent by reading from the first nonempty row to the end of the data or the footer range. The number of
columns in the specified range must match the number specified in the
Example:
|
Multiple Row Ranges | Specify multiple row ranges to read with an
A valid array of multiple row ranges must:
Use of Example:
|
Unspecified or Empty | Do not fetch any data. Example:
|
Example: "DataRange"
, "B2:H15"
Data Types: char
| string
| cell
| single
| double
RowNamesRange
— Location of row names
character vector | string scalar | positive scalar integer | ""
empty character array
Location of row names, specified as a character vector, string scalar, positive scalar
integer, or an empty character array. Specify RowNamesRange
as one of the
values in this table.
Specified by | Behavior |
---|---|
| Specify the starting cell for the data, using Excel
Example:
|
Rectangular Range | Specify the exact range to read using the rectangular range form, where
The number of rows
contained in Example:
|
Row Range | Specify range by identifying the beginning and ending rows using Excel row numbers. Row names must be in a single column. Example:
|
Number Index | Specify the column containing the row names using a positive scalar column index. Example:
|
Unspecified or Empty | Indicate that there are no row names. Example:
|
Example: "RowNamesRange"
, "A1:H1"
Data Types: char
| single
| double
VariableNamesRange
— Location of variable names
character vector | string scalar | positive scalar integer | ""
empty character array
Location of variable names, specified as a character vector, string scalar, positive
scalar integer, or an empty character array. Specify VariableNamesRange
as
one of the values in this table.
Specified by | Behavior |
---|---|
| Specify the starting cell for the data, using Excel
Example:
|
Rectangular Range | Specify the exact range to read using the rectangular range form, where
The number of columns must
match the number specified in the Example:
|
Row Range | Specify range by identifying the beginning and ending rows using Excel row numbers. Must be a single row. Example:
|
Number Index | Specify the row containing the variable names using a positive scalar row index. Example:
|
Unspecified or Empty | Indicate that there are no variable names. Example:
|
Example: "VariableNamesRange"
,
"A1:A15"
Data Types: char
| single
| double
VariableUnitsRange
— Location of variable units
character vector | string scalar | positive scalar integer | ""
empty character array
Location of variable units, specified as a character vector, string scalar, positive
scalar integer, or an empty character array. Specify VariableUnitsRange
as
one of the values in this table.
Specified by | Behavior |
---|---|
| Specify the starting cell for the data, using Excel
Example:
|
Rectangular Range | Specify the exact range to read using the rectangular range form, where
The number of columns must
match the number specified in the Example:
|
Row Range | Specify range by identifying the beginning and ending rows using Excel row numbers. Must be a single row. Example:
|
Number Index | Specify the row containing the data units using a positive scalar row index. Example:
|
Unspecified or Empty | Indicate that there are no variable units. Example:
|
Example: "VariableUnitsRange"
,
"A1:A5"
Data Types: char
| string
| single
| double
VariableDescriptionsRange
— Location of variable descriptions
character vector | string scalar | ""
empty character array
Location of variable descriptions, specified as a character vector, string scalar,
positive scalar integer, or an empty character array. Specify
VariableDescriptionRange
as one of the values in this table.
Specified by | Behavior |
---|---|
| Specify the starting cell for the data, using Excel
Example:
|
Rectangular Range | Specify the exact range to read using the rectangular range form, where
The number of columns must
match the number specified in the Example:
|
Row Range | Specify range by identifying the beginning and ending rows using Excel row numbers. Must be a single row. Example:
|
Number Index | Specify the row containing the descriptions using a positive scalar row index. Example:
|
Unspecified or Empty | Indicate that there are no variable descriptions. Example:
|
Example: "VariableDescriptionsRange"
,
"B1:B15"
Data Types: char
| string
| single
| double
TextType
— Type for imported text data
"string"
| "char"
Type for imported text data, specified as one of these values:
"string"
— Import text data as string arrays."char"
— Import text data as character vectors.
Example: "TextType","char"
DatetimeType
— Type for imported date and time data
"datetime"
(default) | "text"
| "exceldatenum"
(spreadsheet files only)
Type for imported date and time data, specified as DatetimeType
and
one of these values: "datetime"
, "text"
, or
"exceldatenum"
. The value "exceldatenum"
is applicable
only for spreadsheet files, and is not valid for text files.
Value | Type for Imported Date and Time Data |
---|---|
"datetime" | MATLAB
For more information, see |
"text" | If
|
"exceldatenum"
| Excel serial date numbers A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see Differences between the 1900 and the 1904 date system in Excel. |
Example: "DatetimeType","datetime"
VariableNamingRule
— Flag to preserve variable names
"modify"
(default) | "preserve"
Flag to preserve variable names, specified as either "modify"
or
"preserve"
.
"modify"
— Convert invalid variable names (as determined by theisvarname
function) to valid MATLAB identifiers."preserve"
— Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.
Starting in R2019b, variable names and row names can include any characters, including
spaces and non-ASCII characters. Also, they can start with any characters, not just letters.
Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname
function). To preserve these variable names and row names, set the
value of VariableNamingRule
to "preserve"
. Variable
names are not refreshed when the value of VariableNamingRule
is changed
from "modify"
to "preserve"
.
Example: "VariableNamingRule","preserve"
ImportErrorRule
— Procedure to handle import errors
"fill"
(default) | "error"
| "omitrow"
| "omitvar"
Procedure to handle import errors, specified as one of the values in this table. An
import error occurs when readtable
is unable to convert data to the
expected data type or the cell has the Microsoft error data type.
Import Error Rule | Behavior |
---|---|
"fill" | Replace the data where the error occurred with the contents of the
The |
"error" | Stop importing and display an error message showing the error-causing record and field. |
"omitrow" | Omit rows where errors occur. |
"omitvar" | Omit variables where errors occur. |
Example: "ImportErrorRule","omitvar"
WebOptions
— HTTP
or HTTPS
request options
weboptions
object
HTTP
or HTTPS
request options, specified as a
weboptions
object. The weboptions
object determines how to
import data when the specified filename
is an internet URL containing the
protocol type "http://"
or "https://"
.
ReadVariableNames
— Read first row as variable names
true
| false
| 1
| 0
Indicator for reading the first row as variable names, specified as
ReadVariableNames
and either true
,
false
, 1
, or 0
. If unspecified,
readtable
automatically detects the presence of variable
names.
Indicator | Description |
---|---|
| Use when the first row of the region to read contains the variable names for
the table. |
| Use when the first row of the region to read contains data in the table.
|
unspecified | When left unspecified, readtable automatically detects
true or false and proceeds accordingly. |
Note: If both the
"ReadVariableNames"
and "ReadRowNames"
logical
indicators are true
, then readtable
saves the name in
the first column of the first row of the region to read as the first dimension name in the
property, T.Properties.DimensionNames
.
If you specify the ReadVariableNames
argument in addition to
opts
the import options, then the readtable
behavior
changes based on the specification:
If
ReadVariableNames
istrue
, then read the variable names from the specified file by using theVariableNamesRange
or theVariableNamesLine
property of the import options object.If
ReadVariableNames
isfalse
, then read the variable names from theVariableNames
property of the import options object.
Example: "ReadVariableNames",true
ExpectedNumVariables
— Expected number of variables
positive integer
Expected number of variables, specified as ExpectedNumVariables
and a
positive integer. If unspecified, readtable
automatically detects the
number of variables.
Example: "ExpectedNumVariables",5
Data Types: single
| double
Sheet
— Worksheet to read
1
(default) | positive integer | character vector | string scalar
Worksheet to read, specified as Sheet
and a positive integer
indicating the worksheet index or a character vector or string scalar containing the
worksheet name. The worksheet name cannot contain a colon (:
). To
determine the names of sheets in a spreadsheet file, use sheets =
sheetnames(filename)
. For more information, see sheetnames
.
If you specify the Sheet
argument in addition to
opts
the import options, then the readtable
function
uses the specified value for Sheet
argument, overriding the sheet name
defined in the import options.
Example: "Sheet"
, 2
Example: 'Sheet'
, 'MySheetName'
Example: "Sheet"
, "MySheetName"
Data Types: char
| string
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
UseExcel
— Flag to start instance of Microsoft Excel for Windows
false
(default) | true
Flag to start an instance of Microsoft
Excel for Windows when reading spreadsheet data, specified as UseExcel
and
either true
, or false
.
You can set the "UseExcel"
parameter to one of these values:
true
—readtable
starts an instance of Microsoft Excel when reading the file.false
—readtable
does not start an instance of Microsoft Excel when reading the file. When operating in this mode,readtable
functionality differs in the support of file formats and interactive features, such as formulas and macros.
UseExcel |
|
|
---|---|---|
Supported file formats |
|
|
Support for interactive features, such as formulas and macros | Yes | No |
When reading from spreadsheet files on Windows platforms, if you want to start an instance of Microsoft
Excel, then set the "UseExcel"
parameter to
true
.
UseExcel
is not supported in noninteractive, automated
environments.
Example: "UseExcel",true
MergedCellColumnRule
— Rule for cells merged across columns
"placeleft"
(default) | "placeright"
| "duplicate"
| "omitrow"
| "error"
Since R2024b
Rule for cells merged across columns, specified as one of the values in this table.
Import Rule | Behavior |
---|---|
"placeleft" | Place the data in the leftmost cell and fill the remaining cells with the
contents of the You can specify the
|
"placeright" | Place the data in the rightmost cell and fill the remaining cells with the
contents of the You can specify the
|
"duplicate" | Duplicate the data in all cells. |
"omitrow" | Omit rows where merged cells occur. |
"error" | Display an error message and cancel the import operation. |
MergedCellRowRule
— Rule for cells merged across rows
"placetop"
(default) | "placebottom"
| "duplicate"
| "omitvar"
| "error"
Since R2024b
Rule for cells merged across rows, specified as one of the values in this table.
Import Rule | Behavior |
---|---|
"placetop" | Place the data in the top cell and fill the remaining cells with the
contents of the You can specify the
|
"placebottom" | Place the data in the bottom cell and fill the remaining cells with the
contents of the You can specify the
|
"duplicate" | Duplicate the data in all cells. |
"omitvar" | Omit variables where merged cells occur. |
"error" | Display an error message and cancel the import operation. |
FileType
— Type of file
"spreadsheet"
| "text"
| "delimitedtext"
| "fixedwidth"
| "xml"
| "worddocument"
| "html"
Type of file, specified as one of these values.
Value | File Type |
---|---|
"spreadsheet" | Spreadsheet files |
"text" | Text files |
"delimitedtext" | Delimited text files |
"fixedwidth" | Fixed-width text files |
"xml" | XML files |
"worddocument" | Microsoft Word document |
"html" | HTML files |
Use the "FileType"
name-value pair argument when
filename
does not include the file extension, or when the extension is
not one of these:
.txt
,.dat
, or.csv
for text files.xls
,.xlsb
,.xlsm
,.xlsx
,.xltm
,.xltx
, or.ods
for spreadsheet files.xml
, for XML files.docx
for Microsoft Word document files.html
,.xhtml
, or.htm
for HTML files
Example: "FileType","text"
ReadRowNames
— Option to read the first column as row names
false
or 0
(default) | true
or 1
Option to read the first column as row names, specified as a numeric or logical
1
(true
) or 0
(false
).
Set
ReadRowNames
totrue
when the first column of the region to read contains the row names for the table.Set
ReadRowNames
tofalse
when the first column of the region to read contains data, not the row names for the table.
If both the ReadVariableNames
and ReadRowNames
name-value arguments are true
, then readtable
saves the
name in the first column of the first row of the region to read as the first dimension name
in the property, T.Properties.DimensionNames
.
If you specify the ReadRowNames
argument in addition to an import
options object, then the readtable
behavior changes based on the specification:
If
ReadRowNames
istrue
, then read the row names from the specified file by using theRowNamesColumn
(DelimitedTextImportOptions
,FixedWidthImportOptions
),RowNamesRange
(SpreadsheetImportOptions
), orRowNamesSelector
(XMLImportOptions
) property of the respective import options object.If
ReadRowNames
isfalse
, then do not import row names.
If you use the import options syntax without specifying ReadRowNames
,
readtable
uses the value associated with the import options object and
its ReadRowNames
name-value argument.
Example: "ReadRowNames",true
TreatAsMissing
— Placeholder text to treat as empty value
character vector | cell array of character vectors | string scalar | string array
Placeholder text to treat as an empty value, specified as
TreatAsMissing
and a character vector, cell array of character vectors,
string scalar, or string array. Table elements corresponding to these characters are set to
the missing value associated with the data type. For more information, see fillmissing
.
Example: 'TreatAsMissing','N/A'
or
"TreatAsMissing","N/A"
sets N/A
within numeric columns
to NaN
.
Example: 'TreatAsMissing',{'.','NA','N/A'}
or
"TreatAsMissing",[".","NA","N/A"]
sets .
,
NA
and N/A
within numeric columns to
NaN
.
MissingRule
— Procedure to manage missing data
"fill"
(default) | "error"
| "omitrow"
| "omitvar"
Procedure to manage missing data, specified as one of the values in this table. Data is considered missing if an expected node does not exist.
Missing Rule | Behavior |
---|---|
"fill" | Replace missing data with the contents of the The |
"error" | Stop importing and display an error message showing the missing record and field. |
"omitrow" | Omit rows that contain missing data. |
"omitvar" | Omit variables that contain missing data. |
Example: "MissingRule","omitrow"
TextType
— Type for imported text data
"string"
| "char"
Type for imported text data, specified as one of these values:
"string"
— Import text data as string arrays."char"
— Import text data as character vectors.
Example: "TextType","char"
DatetimeType
— Type for imported date and time data
"datetime"
(default) | "text"
| "exceldatenum"
(spreadsheet files only)
Type for imported date and time data, specified as DatetimeType
and
one of these values: "datetime"
, "text"
, or
"exceldatenum"
. The value "exceldatenum"
is applicable
only for spreadsheet files, and is not valid for text files.
Value | Type for Imported Date and Time Data |
---|---|
"datetime" | MATLAB
For more information, see |
"text" | If
|
"exceldatenum"
| Excel serial date numbers A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see Differences between the 1900 and the 1904 date system in Excel. |
Example: "DatetimeType","datetime"
VariableNamingRule
— Flag to preserve variable names
"modify"
(default) | "preserve"
Flag to preserve variable names, specified as either "modify"
or
"preserve"
.
"modify"
— Convert invalid variable names (as determined by theisvarname
function) to valid MATLAB identifiers."preserve"
— Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.
Starting in R2019b, variable names and row names can include any characters, including
spaces and non-ASCII characters. Also, they can start with any characters, not just letters.
Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname
function). To preserve these variable names and row names, set the
value of VariableNamingRule
to "preserve"
. Variable
names are not refreshed when the value of VariableNamingRule
is changed
from "modify"
to "preserve"
.
Example: "VariableNamingRule","preserve"
ImportErrorRule
— Procedure to handle import errors
"fill"
(default) | "error"
| "omitrow"
| "omitvar"
Procedure to handle import errors, specified as one of the values in this table. An
import error occurs when readtable
is unable to convert text to the
expected data type.
Import Error Rule | Behavior |
---|---|
"fill" | Replace the data where the error occurred with the contents of the
The |
"error" | Stop importing and display an error message showing the error-causing record and field. |
"omitrow" | Omit rows where errors occur. |
"omitvar" | Omit variables where errors occur. |
Example: "ImportErrorRule","omitvar"
WebOptions
— HTTP
or HTTPS
request options
weboptions
object
HTTP
or HTTPS
request options, specified as a
weboptions
object. The weboptions
object determines how to
import data when the specified filename
is an internet URL containing the
protocol type "http://"
or "https://"
.
AttributeSuffix
— Attribute suffix
"Attribute"
(default) | character vector | string scalar
Attribute suffix, specified as AttributeSuffix
and either a character
vector or string scalar. This argument specifies the suffix the reading function appends to
all table variables that correspond to attributes in the input XML file. If you do not
specify AttributeSuffix
, then the reading function defaults to appending
the suffix "Attribute"
to all variable names corresponding to attributes
in the input XML file.
Example: "AttributeSuffix","_att"
ImportAttributes
— Import attributes
logical 1
or true
(default) | logical 0
or false
Import attributes, specified as ImportAttributes
and either
1
(true
) or 0
(false
). If you specify false
, then the reading
function will not import the XML attributes in the input file as variables in the output
table.
Example: "ImportAttributes",false
RowNodeName
— Table row XML node name
character vector | string scalar
Table row XML node name, specified as RowNodeName
and either a
character vector or string scalar. This argument specifies the XML node name that delineates
rows of the output table.
Example: "RowNodeName","XMLNodeName"
RowSelector
— Table row XPath expression
character vector | string scalar
Table row XPath expression, specified as a character vector or string scalar that the
reading function uses to select individual rows of the output table. You must specify
RowSelector
as a valid XPath version 1.0 expression.
Example: "RowSelector","/RootNode/ChildNode"
VariableNodeNames
— Table variable XML node names
cell array of character vectors | string array
Table variable XML node names, specified as VariableNodeNames
and
either a cell array of character vectors or string array. This argument specifies the XML
node name that the reading function uses to identify the XML nodes to read as variables in
the output table.
Example: "VariableNodeNames",{'XMLNodeName1','XMLNodeName2'}
Example: 'VariableNodeNames',"XMLNodeName"
Example: 'VariableNodeNames',["XMLNodeName1","XMLNodeName2"]
VariableSelectors
— Table variable XPath expressions
cell array of character vectors | string array
Table variable XPath expressions, specified as a cell array of character vectors or
string array that the reading function uses to select table variables. You must specify
VariableSelectors
as valid XPath version 1.0 expressions.
Use XPath selectors to specify which elements of the
XML input document to import. For example, suppose you want to import the XML file
myFile.xml
, which has the following structure:
<data> <table category="ones"> <var>1</var> <var>2</var> </table> <table category="tens"> <var>10</var> <var>20</var> </table> </data>
Selection Operation | Syntax | Example |
---|---|---|
Select every node whose name matches the node you want to select, regardless of its location in the document. | Prefix the name with two forward slashes (// ). | To select every node named "var", use: data = readtable("myFile.xml", "VariableSelectors", "//var") |
Read the value of an attribute belonging to an element node. | Prefix the attribute with an at sign (@ ). | To select the value of the category attribute of the table node, use: data = readtable("myFile.xml", "VariableSelectors", "//table/@category") |
Select a specific node in a set of nodes. | Provide the index of the node you want to select in square brackets
([] ). | To select the first var node of each table node, use: data = readtable("myFile.xml", "VariableSelectors", "//var[1]") |
Specify precedence of operations. | Add parentheses around the expression you want to evaluate first. | To select the first value of each var node, use: data = readtable("myFile.xml", "VariableSelectors", "//table/var[1]") |
To select the first value of the first var node, use: data = readtable("myFile.xml", "VariableSelectors", "(//table/var)[1]") |
TableNodeName
— Table XML node name
character vector | string scalar
Table XML node name, specified as TableNodeName
and either a
character vector or string scalar. This argument specifies the node in the input structure
that the reading function should read to a table.
Example: "TableNodeName","NodeName"
VariableUnitsSelector
— Variable units XPath expression
character vector | string scalar
Variable units XPath, specified as a character vector or string scalar that the reading
function uses to select the table variable units. You must specify
VariableUnitsSelector
as a valid XPath version 1.0 expression.
Example: "VariableUnitsSelector","/RootNode/ChildNode"
VariableDescriptionsSelector
— Variable descriptions XPath expression
character vector | string scalar
Variable descriptions XPath expression, specified as a character vector or string scalar
that the reading function reads uses to select the table variable descriptions. You must
specify VariableDescriptionsSelector
as a valid XPath version 1.0
expression.
Example: "VariableDescriptionsSelector","/RootNode/ChildNode"
RowNamesSelector
— Table row names XPath expression
character vector | string scalar
Table row names XPath expression, specified as a character vector or string scalar that
the reading function uses to select the names of the table rows. You must specify
RowNamesSelector
as a valid XPath version 1.0 expression.
Example: "RowNamesSelector","/RootNode/ChildNode"
RepeatedNodeRule
— Procedure to handle repeated XML nodes
"addcol"
(default) | "ignore"
| "error"
Procedure to handle repeated XML nodes in a given row of a table, specified as
"addcol"
, "ignore"
, or
"error"
.
Repeated Node Rule | Behavior |
---|---|
"addcol" | Add columns for the repeated nodes under the variable header in the table.
Specifying the value of |
"ignore" | Skip importing the repeated nodes. |
"error" | Display an error message and abort the import operation. |
Example: "RepeatedNodeRule","ignore"
RegisteredNamespaces
— Set of registered XML namespace prefixes
string array
Set of registered XML namespace prefixes, specified as
RegisteredNamespaces
and an array of prefixes. The reading function uses
these prefixes when evaluating XPath expressions on an XML file. Specify the namespace
prefixes and their associated URLs as an Nx2 string array.
RegisteredNamespaces
can be used when you also evaluate an XPath
expression specified by a selector name-value argument, such as
StructSelector
for readstruct
, or
VariableSelectors
for readtable
and
readtimetable
.
By default, the reading function automatically detects namespace prefixes to register
for use in XPath evaluation, but you can also register new namespace prefixes using the
RegisteredNamespaces
name-value argument. You might register a new
namespace prefix when an XML node has a namespace URL, but no declared namespace prefix in
the XML file.
For example, evaluate an XPath expression on an XML file called
example.xml
that does not contain a namespace prefix. Specify
"RegisteredNamespaces"
as ["myprefix",
"https://www.mathworks.com"]
to assign the prefix myprefix
to
the URL https://www.mathworks.com
.
T = readtable("example.xml", "VariableSelector", "/myprefix:Data",... "RegisteredNamespaces", ["myprefix", "https://www.mathworks.com"])
Example: "RegisteredNamespaces",["myprefix",
"https://www.mathworks.com"]
TableSelector
— Table data XPath expression
character vector | string scalar
Table data XPath expression, specified as a character vector or string scalar that the
reading function uses to select the output table data. You must specify
TableSelector
as a valid XPath version 1.0 expression. Use XPath
selectors to specify which elements of the XML input document to import.
Selection Operation | Syntax |
---|---|
Select every node whose name matches the node you want to select, regardless of its location in the document. | Prefix the name with two forward slashes (// ). |
Select the value of an attribute belonging to an element node. | Prefix the attribute with an at sign (@ ). |
Select a specific node in a set of nodes. | Provide the index of the node you want to select in square brackets
([] ). |
Specify precedence of operations. | Add parentheses around the expression you want to evaluate first. |
Example: "myFile.xml", "TableSelector", "//table[1]"
FileType
— Type of file
"spreadsheet"
| "text"
| "delimitedtext"
| "fixedwidth"
| "xml"
| "worddocument"
| "html"
Type of file, specified as one of these values.
Value | File Type |
---|---|
"spreadsheet" | Spreadsheet files |
"text" | Text files |
"delimitedtext" | Delimited text files |
"fixedwidth" | Fixed-width text files |
"xml" | XML files |
"worddocument" | Microsoft Word document |
"html" | HTML files |
Use the "FileType"
name-value pair argument when
filename
does not include the file extension, or when the extension is
not one of these:
.txt
,.dat
, or.csv
for text files.xls
,.xlsb
,.xlsm
,.xlsx
,.xltm
,.xltx
, or.ods
for spreadsheet files.xml
, for XML files.docx
for Microsoft Word document files.html
,.xhtml
, or.htm
for HTML files
Example: "FileType","text"
ReadRowNames
— Option to read first column as row names
false
or 0
(default) | true
or 1
Option to read the first column as row names,specified as a numeric or logical
1
(true
) or 0
(false
).
Set
ReadRowNames
totrue
when the first column of the region to read contains the row names for the table.Set
ReadRowNames
tofalse
when the first column of the region to read contains data, not the row names for the table.
If both the ReadVariableNames
and ReadRowNames
name-value arguments are true
, then readtable
saves the
name in the first column of the first row of the region to read as the first dimension name
in the property, T.Properties.DimensionNames
.
If you specify the ReadRowNames
argument in addition to an import
options object, then the readtable
behavior changes based on the specification:
If
ReadRowNames
istrue
, then read the row names from the specified file by using theRowNamesColumn
(DelimitedTextImportOptions
,FixedWidthImportOptions
),RowNamesRange
(SpreadsheetImportOptions
), orRowNamesSelector
(XMLImportOptions
) property of the respective import options object.If
ReadRowNames
isfalse
, then do not import row names.
If you use the import options syntax without specifying ReadRowNames
,
readtable
uses the value associated with the import options object and
its ReadRowNames
name-value argument.
Example: "ReadRowNames",true
TreatAsMissing
— Placeholder text to treat as empty value
character vector | cell array of character vectors | string scalar | string array
Placeholder text to treat as an empty value, specified as
TreatAsMissing
and a character vector, cell array of character vectors,
string scalar, or string array. Table elements corresponding to these characters are set to
the missing value associated with the data type. For more information, see fillmissing
.
Example: 'TreatAsMissing','N/A'
or
"TreatAsMissing","N/A"
sets N/A
within numeric columns
to NaN
.
Example: 'TreatAsMissing',{'.','NA','N/A'}
or
"TreatAsMissing",[".","NA","N/A"]
sets .
,
NA
and N/A
within numeric columns to
NaN
.
MissingRule
— Procedure to manage missing data
"fill"
(default) | "error"
| "omitrow"
| "omitvar"
Procedure to manage missing data, specified as one of the values in this table. Data is considered missing if an expected field in a row does not exist.
Missing Rule | Behavior |
---|---|
"fill" | Replace missing data with the contents of the The |
"error" | Stop importing and display an error message showing the missing record and field. |
"omitrow" | Omit rows that contain missing data. |
"omitvar" | Omit variables that contain missing data. |
Example: "MissingRule","omitrow"
EmptyRowRule
— Rule to apply to empty rows in the table
"skip"
(default) | "read"
| "error"
Rule to apply to empty rows in the table, specified as one of the following:
"skip"
– Skip empty rows."read"
– Read empty rows."error"
– Ignore empty rows during table detection and error when reading.
Example: "EmptyRowRule","read"
EmptyColumnRule
— Rule to apply to empty columns in the table
"skip"
(default) | "read"
| "error"
Rule to apply to empty columns in the table, specified as one of the following:
"skip"
– Skip empty columns."read"
– Read empty columns."error"
– Ignore empty columns during table detection and error when reading.
Example: "EmptyColumnRule","error"
TextType
— Type for imported text data
"string"
| "char"
Type for imported text data, specified as one of these values:
"string"
— Import text data as string arrays."char"
— Import text data as character vectors.
Example: "TextType","char"
DatetimeType
— Type for imported date and time data
"datetime"
(default) | "text"
| "exceldatenum"
(spreadsheet files only)
Type for imported date and time data, specified as DatetimeType
and
one of these values: "datetime"
, "text"
, or
"exceldatenum"
. The value "exceldatenum"
is applicable
only for spreadsheet files, and is not valid for text files.
Value | Type for Imported Date and Time Data |
---|---|
"datetime" | MATLAB
For more information, see |
"text" | If
|
"exceldatenum"
| Excel serial date numbers A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see Differences between the 1900 and the 1904 date system in Excel. |
Example: "DatetimeType","datetime"
VariableNamingRule
— Flag to preserve variable names
"modify"
(default) | "preserve"
Flag to preserve variable names, specified as either "modify"
or
"preserve"
.
"modify"
— Convert invalid variable names (as determined by theisvarname
function) to valid MATLAB identifiers."preserve"
— Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.
Starting in R2019b, variable names and row names can include any characters, including
spaces and non-ASCII characters. Also, they can start with any characters, not just letters.
Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname
function). To preserve these variable names and row names, set the
value of VariableNamingRule
to "preserve"
. Variable
names are not refreshed when the value of VariableNamingRule
is changed
from "modify"
to "preserve"
.
Example: "VariableNamingRule","preserve"
ImportErrorRule
— Procedure to handle import errors
"fill"
(default) | "error"
| "omitrow"
| "omitvar"
Procedure to handle import errors, specified as one of the values in this table. An
import error occurs when readtable
is unable to convert text to the
expected data type.
Import Error Rule | Behavior |
---|---|
"fill" | Replace the data where the error occurred with the contents of the
The |
"error" | Stop importing and display an error message showing the error-causing record and field. |
"omitrow" | Omit rows where errors occur. |
"omitvar" | Omit variables where errors occur. |
Example: "ImportErrorRule","omitvar"
WebOptions
— HTTP
or HTTPS
request options
weboptions
object
HTTP
or HTTPS
request options, specified as a
weboptions
object. The weboptions
object determines how to
import data when the specified filename
is an internet URL containing the
protocol type "http://"
or "https://"
.
TableIndex
— Index of table to read
1
(default) | positive integer
Index of table to read from Microsoft Word document or HTML file containing multiple tables, specified as a positive integer.
When you specify TableIndex
, the software automatically sets
TableSelector
to the equivalent XPath expression.
Example: "TableIndex",2
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
MergedCellColumnRule
— Rule for cells merged across columns
"placeleft"
(default) | "placeright"
| "duplicate"
| "omitrow"
| "error"
Rule for cells merged across columns, specified as one of the values in this table.
Import Rule | Behavior |
---|---|
"placeleft" | Place the data in the leftmost cell and fill the remaining cells with the
contents of the You can specify the
|
"placeright" | Place the data in the rightmost cell and fill the remaining cells with the
contents of the You can specify the
|
"duplicate" | Duplicate the data in all cells. |
"omitrow" | Omit rows where merged cells occur. |
"error" | Display an error message and cancel the import operation. |
MergedCellRowRule
— Rule for cells merged across rows
"placetop"
(default) | "placebottom"
| "duplicate"
| "omitvar"
| "error"
Rule for cells merged across rows, specified as one of the values in this table.
Import Rule | Behavior |
---|---|
"placetop" | Place the data in the top cell and fill the remaining cells with the
contents of the You can specify the
|
"placebottom" | Place the data in the bottom cell and fill the remaining cells with the
contents of the You can specify the
|
"duplicate" | Duplicate the data in all cells. |
"omitvar" | Omit variables where merged cells occur. |
"error" | Display an error message and cancel the import operation. |
VariableNamesRow
— Row containing variable names
nonnegative integer
Row containing variable names, specified as a nonnegative integer.
If you do not specify
VariableNamesRow
, then the software reads variable names according to theReadVariableNames
argument.If
VariableNamesRow
is0
, then the software does not import the variable names.Otherwise, the software imports the variable names from the specified row.
Example: "VariableNamesRow",2
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
VariableUnitsRow
— Row containing variable units
0
(default) | nonnegative integer
Row containing variable units, specified as a nonnegative integer.
If VariableUnitsRow
is 0
, then the software does
not import the variable units. Otherwise, the software imports the variable units from the
specified row.
Example: "VariableUnitsRow",3
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
VariableDescriptionsRow
— Row containing variable descriptions
0
(default) | nonnegative integer
Row containing variable descriptions, specified as a nonnegative integer.
If VariableDescriptionsRow
is 0
, then the software
does not import the variable descriptions. Otherwise, the software imports the variable
descriptions from the specified row.
Example: "VariableDescriptionsRow",4
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
TableSelector
— Table data XPath expression
character vector | string scalar
Table data XPath expression, specified as a character vector or string scalar that the
reading function uses to select the output table data. You must specify
TableSelector
as a valid XPath version 1.0 expression. Use XPath
selectors to specify which elements of the XML input document to import.
Selection Operation | Syntax |
---|---|
Select every node whose name matches the node you want to select, regardless of its location in the document. | Prefix the name with two forward slashes (// ). |
Select the value of an attribute belonging to an element node. | Prefix the attribute with an at sign (@ ). |
Select a specific node in a set of nodes. | Provide the index of the node you want to select in square brackets
([] ). |
Specify precedence of operations. | Add parentheses around the expression you want to evaluate first. |
Example: "TableSelector","/RootNode/ChildNode"
Example: "myFile.xml", "TableSelector", "//table[1]"
FileType
— Type of file
"spreadsheet"
| "text"
| "delimitedtext"
| "fixedwidth"
| "xml"
| "worddocument"
| "html"
Type of file, specified as one of these values.
Value | File Type |
---|---|
"spreadsheet" | Spreadsheet files |
"text" | Text files |
"delimitedtext" | Delimited text files |
"fixedwidth" | Fixed-width text files |
"xml" | XML files |
"worddocument" | Microsoft Word document |
"html" | HTML files |
Use the "FileType"
name-value pair argument when
filename
does not include the file extension, or when the extension is
not one of these:
.txt
,.dat
, or.csv
for text files.xls
,.xlsb
,.xlsm
,.xlsx
,.xltm
,.xltx
, or.ods
for spreadsheet files.xml
, for XML files.docx
for Microsoft Word document files.html
,.xhtml
, or.htm
for HTML files
Example: "FileType","text"
ReadRowNames
— Option to read first column as row names
false
or 0
(default) | true
or 1
Option to read the first column as row names, specified as a numeric or logical
1
(true
) or 0
(false
).
Set
ReadRowNames
totrue
when the first column of the region to read contains the row names for the table.Set
ReadRowNames
tofalse
when the first column of the region to read contains data, not the row names for the table.
If both the ReadVariableNames
and ReadRowNames
name-value arguments are true
, then readtable
saves the
name in the first column of the first row of the region to read as the first dimension name
in the property T.Properties.DimensionNames
.
If you specify the ReadRowNames
argument in addition to an import
options object, then the readtable
behavior changes based on the specification:
If
ReadRowNames
istrue
, then read the row names from the specified file by using theRowNamesColumn
(DelimitedTextImportOptions
,FixedWidthImportOptions
),RowNamesRange
(SpreadsheetImportOptions
), orRowNamesSelector
(XMLImportOptions
) property of the respective import options object.If
ReadRowNames
isfalse
, then do not import row names.
If you use the import options syntax without specifying ReadRowNames
,
readtable
uses the value associated with the import options object and
its ReadRowNames
name-value argument.
Example: "ReadRowNames",true
TreatAsMissing
— Placeholder text to treat as empty value
character vector | cell array of character vectors | string scalar | string array
Placeholder text to treat as an empty value, specified as
TreatAsMissing
and a character vector, cell array of character vectors,
string scalar, or string array. Table elements corresponding to these characters are set to
the missing value associated with the data type. For more information, see fillmissing
.
Example: "TreatAsMissing","N/A"
or
"TreatAsMissing","N/A"
sets N/A
within numeric columns
to NaN
.
Example: 'TreatAsMissing',{'.','NA','N/A'}
or
"TreatAsMissing",[".","NA","N/A"]
sets .
,
NA
and N/A
within numeric columns to
NaN
.
MissingRule
— Procedure to manage missing data
"fill"
(default) | "error"
| "omitrow"
| "omitvar"
Procedure to manage missing data, specified as one of the values in this table. Data is considered missing if an expected field in a row does not exist.
Missing Rule | Behavior |
---|---|
"fill" | Replace missing data with the contents of the The |
"error" | Stop importing and display an error message showing the missing record and field. |
"omitrow" | Omit rows that contain missing data. |
"omitvar" | Omit variables that contain missing data. |
Example: "MissingRule","omitrow"
EmptyRowRule
— Rule to apply to empty rows in the table
"skip"
(default) | "read"
| "error"
Rule to apply to empty rows in the table, specified as one of the following:
"skip"
– Skip empty rows."read"
– Read empty rows."error"
– Ignore empty rows during table detection and error when reading.
Example: "EmptyRowRule","read"
EmptyColumnRule
— Rule to apply to empty columns in the table
"skip"
(default) | "read"
| "error"
Rule to apply to empty columns in the table, specified as one of the following:
"skip"
– Skip empty columns."read"
– Read empty columns."error"
– Ignore empty columns during table detection and error when reading.
Example: "EmptyColumnRule","error"
TextType
— Type for imported text data
"string"
| "char"
Type for imported text data, specified as one of these values:
"string"
— Import text data as string arrays."char"
— Import text data as character vectors.
Example: "TextType","char"
DatetimeType
— Type for imported date and time data
"datetime"
(default) | "text"
| "exceldatenum"
(spreadsheet files only)
Type for imported date and time data, specified as DatetimeType
and
one of these values: "datetime"
, "text"
, or
"exceldatenum"
. The value "exceldatenum"
is applicable
only for spreadsheet files, and is not valid for text files.
Value | Type for Imported Date and Time Data |
---|---|
"datetime" | MATLAB
For more information, see |
"text" | If
|
"exceldatenum"
| Excel serial date numbers A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see Differences between the 1900 and the 1904 date system in Excel. |
Example: "DatetimeType","datetime"
VariableNamingRule
— Flag to preserve variable names
"modify"
(default) | "preserve"
Flag to preserve variable names, specified as either "modify"
or
"preserve"
.
"modify"
— Convert invalid variable names (as determined by theisvarname
function) to valid MATLAB identifiers."preserve"
— Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.
Starting in R2019b, variable names and row names can include any characters, including
spaces and non-ASCII characters. Also, they can start with any characters, not just letters.
Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname
function). To preserve these variable names and row names, set the
value of VariableNamingRule
to "preserve"
. Variable
names are not refreshed when the value of VariableNamingRule
is changed
from "modify"
to "preserve"
.
Example: "VariableNamingRule","preserve"
ImportErrorRule
— Procedure to handle import errors
"fill"
(default) | "error"
| "omitrow"
| "omitvar"
Procedure to handle import errors, specified as one of the values in this table. An
import error occurs when readtable
is unable to convert text to the
expected data type.
Import Error Rule | Behavior |
---|---|
"fill" | Replace the data where the error occurred with the contents of the
The |
"error" | Stop importing and display an error message showing the error-causing record and field. |
"omitrow" | Omit rows where errors occur. |
"omitvar" | Omit variables where errors occur. |
Example: "ImportErrorRule","omitvar"
WebOptions
— HTTP
or HTTPS
request options
weboptions
object
HTTP
or HTTPS
request options, specified as a
weboptions
object. The weboptions
object determines how to
import data when the specified filename
is an internet URL containing the
protocol type "http://"
or "https://"
.
TableIndex
— Index of table to read
1
(default) | positive integer
Index of table to read from Microsoft Word document or HTML file containing multiple tables, specified as a positive integer.
When you specify TableIndex
, the software automatically sets
TableSelector
to the equivalent XPath expression.
Example: "TableIndex",2
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
MergedCellColumnRule
— Rule for cells merged across columns
"placeleft"
(default) | "placeright"
| "duplicate"
| "omitrow"
| "error"
Rule for cells merged across columns, specified as one of the values in this table.
Import Rule | Behavior |
---|---|
"placeleft" | Place the data in the leftmost cell and fill the remaining cells with the
contents of the You can specify the
|
"placeright" | Place the data in the rightmost cell and fill the remaining cells with the
contents of the You can specify the
|
"duplicate" | Duplicate the data in all cells. |
"omitrow" | Omit rows where merged cells occur. |
"error" | Display an error message and cancel the import operation. |
MergedCellRowRule
— Rule for cells merged across rows
"placetop"
(default) | "placebottom"
| "duplicate"
| "omitvar"
| "error"
Rule for cells merged across rows, specified as one of the values in this table.
Import Rule | Behavior |
---|---|
"placetop" | Place the data in the top cell and fill the remaining cells with the
contents of the You can specify the
|
"placebottom" | Place the data in the bottom cell and fill the remaining cells with the
contents of the You can specify the
|
"duplicate" | Duplicate the data in all cells. |
"omitvar" | Omit variables where merged cells occur. |
"error" | Display an error message and cancel the import operation. |
VariableNamesRow
— Row containing variable names
nonnegative integer
Row containing variable names, specified as a nonnegative integer.
If you do not specify
VariableNamesRow
, then the software reads variable names according to theReadVariableNames
argument.If
VariableNamesRow
is0
, then the software does not import the variable names.Otherwise, the software imports the variable names from the specified row.
Example: "VariableNamesRow",2
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
VariableUnitsRow
— Row containing variable units
0
(default) | nonnegative integer
Row containing variable units, specified as a nonnegative integer.
If VariableUnitsRow
is 0
, then the software does
not import the variable units. Otherwise, the software imports the variable units from the
specified row.
Example: "VariableUnitsRow",3
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
VariableDescriptionsRow
— Row containing variable descriptions
0
(default) | nonnegative integer
Row containing variable descriptions, specified as a nonnegative integer.
If VariableDescriptionsRow
is 0
, then the software
does not import the variable descriptions. Otherwise, the software imports the variable
descriptions from the specified row.
Example: "VariableDescriptionsRow",4
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
TableSelector
— Table data XPath expression
character vector | string scalar
Table data XPath expression, specified as a character vector or string scalar that the
reading function uses to select the output table data. You must specify
TableSelector
as a valid XPath version 1.0 expression. Use XPath
selectors to specify which elements of the XML input document to import.
Selection Operation | Syntax |
---|---|
Select every node whose name matches the node you want to select, regardless of its location in the document. | Prefix the name with two forward slashes (// ). |
Select the value of an attribute belonging to an element node. | Prefix the attribute with an at sign (@ ). |
Select a specific node in a set of nodes. | Provide the index of the node you want to select in square brackets
([] ). |
Specify precedence of operations. | Add parentheses around the expression you want to evaluate first. |
Example: "TableSelector","/RootNode/ChildNode"
Example: "myFile.xml", "TableSelector", "//table[1]"
Output Arguments
T
— Output table
table
Output table, returned as a table. The table can store metadata such as descriptions, variable
units, variable names, and row names. For more information, see the Properties section
of table
.
Extended Capabilities
Thread-Based Environment
Run code in the background using MATLAB® backgroundPool
or accelerate code with Parallel Computing Toolbox™ ThreadPool
.
Usage notes and limitations:
Text and spreadsheet file workflows are supported in thread-based environments.
Version History
Introduced in R2013bR2024b: Specify how to import merged cells in spreadsheets
When importing data from spreadsheets, you can specify how readtable
imports cells that are merged across rows and columns by using the
MergedCellRowRule
and MergedCellColumnRule
name-value
arguments.
R2023a: Create tables from text and spreadsheet files in thread-based environments
This function supports thread-based environments for text and spreadsheet file workflows.
R2020a: Results of detectImportOptions
function used by default to import tabular data
By default, the readtable
function uses the results of the
detectImportOptions
function to import tabular data. In essence, these two
function calls behave identically.
T = readtable(filename) T = readtable(filename,detectImportOptions(filename))
In R2020a, there are several differences between the default behavior of
readtable
and its default behavior in previous releases.
Description of Input Fields or Rows | Default R2020a | Default Behavior in Previous Releases |
---|---|---|
First row does not have text to assign as names of output table variables | Assigns the names | Converts the values in the first row of data values to the names of output table variables |
Multiple rows of text as header lines |
|
|
Empty fields | Treat as missing values for detected data type | Treat as empty character vectors or strings |
Values in quotes | Treat as detected data type | Treat as text |
Text that cannot be converted | Treat as missing values for detected data type | Treat as text |
Nonnumeric character trails numeric character without delimiter between them | Treat characters as nonnumeric | Treat numeric and nonnumeric characters as though delimiter separated them |
Input text file has lines with different number of delimiters | Returns output table with extra variables | Raises error message |
To call readtable
with the default behavior it had up to R2019b, use
the 'Format','auto'
name-value pair argument.
T = readtable(filename,'Format','auto')
See Also
Functions
writetable
|table
|textscan
|detectImportOptions
|preview
|readtimetable
|readcell
|readmatrix
|readvars
|setvaropts
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