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split

Split strings at delimiters

Description

example

newStr = split(str) divides str at whitespace characters and returns the result as the output array newStr. The input array str can be a string array, character vector, or cell array of character vectors. If str is a string array, then so is newStr. Otherwise, newStr is a cell array of character vectors. newStr does not include the whitespace characters from str.

If str is a string array or cell array of character vectors, and has multiple elements, then each element must be divisible into the same number of substrings.

  • If str is a string scalar or character vector, then newStr is an N-by-1 string array or cell array of character vectors, where N is the number of substrings.

  • If str is an M-by-1 string array or cell array, then newStr is an M-by-N array.

  • If str is a 1-by-M string array or cell array, then newStr is an 1-by-M-by-N array.

For a string array or cell array of any size, split orients the N substrings along the first trailing dimension with a size of 1.

If the number of substrings is not the same for every element of str, then call split in a for-loop to divide the elements of str one at a time.

example

newStr = split(str,delimiter) divides each element of str at the delimiters specified by delimiter. The output newStr does not include the delimiters.

example

newStr = split(str,delimiter,dim) divides each element of str into a vector oriented along the dimension specified by dim.

example

[newStr,match] = split(___) additionally returns an array, match, that contains all occurrences of delimiters at which the split function splits str. You can use this syntax with any of the input arguments of the previous syntaxes.

Examples

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Split names in a string array at whitespace characters. Then reorder the strings and join them so that the last names precede the first names.

Create a 3-by-1 string array containing names. Starting in R2017a, you can create strings using double quotes.

names = ["Mary Butler";
         "Santiago Marquez";
         "Diana Lee"]
names = 3x1 string
    "Mary Butler"
    "Santiago Marquez"
    "Diana Lee"

If you are using R2016b, create string arrays using the string function instead of double quotes.

Split names at whitespace characters, making it a 3-by-2 string array.

names = split(names)
names = 3x2 string
    "Mary"        "Butler" 
    "Santiago"    "Marquez"
    "Diana"       "Lee"    

Switch the columns of names so that the last names are in the first column. Add a comma after each last name.

names = [names(:,2) names(:,1)];
names(:,1) = names(:,1) + ','
names = 3x2 string
    "Butler,"     "Mary"    
    "Marquez,"    "Santiago"
    "Lee,"        "Diana"   

Join the last and first names. The join function places a space character between the strings it joins. After the join, names is a 3-by-1 string array.

names = join(names)
names = 3x1 string
    "Butler, Mary"
    "Marquez, Santiago"
    "Lee, Diana"

Create a string that contains the path to a folder. Starting in R2017a, you can create strings using double quotes.

myPath = "/Users/jdoe/My Documents/Examples"
myPath = 
"/Users/jdoe/My Documents/Examples"

Split the path at the / character. split returns myFolders as a 5-by-1 string array. The first string is "" because myPath starts with the / character.

myFolders = split(myPath,"/")
myFolders = 5x1 string
    ""
    "Users"
    "jdoe"
    "My Documents"
    "Examples"

Join myFolders into a new path with \ as the delimiter. Add C: as the beginning of the path.

myNewPath = join(myFolders,"\");
myNewPath = 'C:' + myNewPath
myNewPath = 
"C:\Users\jdoe\My Documents\Examples"

Since R2020b

Get the numbers from a string by treating text as a delimiter. Use a pattern to match the text. Then add up the numbers.

First, create a string that has numbers in it.

str = "10 apples 3 bananas and 5 oranges"
str = 
"10 apples 3 bananas and 5 oranges"

Then, create a pattern that matches a space character or letters.

pat = " " | lettersPattern
pat = pattern
  Matching:

    " " | lettersPattern

Split the string using pat as the delimiter. The empty strings represent splits between spaces and sequences of letters that had nothing else between them. For example, in "10 apples", there is a split before the delimiter " ", and then between " " and "apples". Since there is nothing between the delimiters " " and "apples", the split function returns an empty string to indicate there is nothing between them.

N = split(str,pat)
N = 11x1 string
    "10"
    ""
    ""
    "3"
    ""
    ""
    ""
    ""
    "5"
    ""
    ""

Discard the empty strings and keep the substrings that represent numbers.

N = N(strlength(N) > 0)
N = 3x1 string
    "10"
    "3"
    "5"

Finally, convert N to a numeric array and sum over it.

N = str2double(N);
sum(N)
ans = 18

For a list of functions that create pattern objects, see pattern.

Create a string. Starting in R2017a, you can create strings using double quotes.

str = "A horse! A horse! My kingdom for a horse!"
str = 
"A horse! A horse! My kingdom for a horse!"

Split str at exclamation points and at whitespace characters. newStr is a 10-by-1 string array. The last string is an empty string, "", because the last character in str is a delimiter.

newStr = split(str,[" ","!"])
newStr = 12x1 string
    "A"
    "horse"
    ""
    "A"
    "horse"
    ""
    "My"
    "kingdom"
    "for"
    "a"
    "horse"
    ""

Create a string array in which each element contains comma-delimited data about a patient. Starting in R2017a, you can create strings using double quotes.

patients = ["LastName,Age,Gender,Height,Weight";
            "Adams,47,F,64,123";
            "Jones,,,68,175";
            "King,,M,66,180";
            "Smith,38,F,63,118"]
patients = 5x1 string
    "LastName,Age,Gender,Height,Weight"
    "Adams,47,F,64,123"
    "Jones,,,68,175"
    "King,,M,66,180"
    "Smith,38,F,63,118"

Split the string array. A pair of commas with nothing between them indicates missing data. When split divides on repeated delimiters, it returns empty strings as corresponding elements of the output array.

patients = split(patients,",")
patients = 5x5 string
    "LastName"    "Age"    "Gender"    "Height"    "Weight"
    "Adams"       "47"     "F"         "64"        "123"   
    "Jones"       ""       ""          "68"        "175"   
    "King"        ""       "M"         "66"        "180"   
    "Smith"       "38"     "F"         "63"        "118"   

Create a 3-by-1 string array containing names. Starting in R2017a, you can create strings using double quotes.

names = ["Mary Butler";
         "Santiago Marquez";
         "Diana Lee"]
names = 3x1 string
    "Mary Butler"
    "Santiago Marquez"
    "Diana Lee"

Split the array at whitespace characters. By default, split orients the output substrings along the first trailing dimension with a size of 1. Because names is a 3-by-1 string array, split orients the substrings along the second dimension of splitNames, that is, the columns.

splitNames = split(names)
splitNames = 3x2 string
    "Mary"        "Butler" 
    "Santiago"    "Marquez"
    "Diana"       "Lee"    

To orient the substrings along the rows, or first dimension, specify the dimension after you specify the delimiter. splitNames is now a 2-by-3 string array, with the first names in the first row and the last names in the second row.

splitNames = split(names," ",1)
splitNames = 2x3 string
    "Mary"      "Santiago"    "Diana"
    "Butler"    "Marquez"     "Lee"  

Create a string. Starting in R2017a, you can create strings using double quotes.

str = "bacon, lettuce, and tomato"
str = 
"bacon, lettuce, and tomato"

Split str on delimiters. Return the results of the split in a string array, and the delimiters in a second string array. When there is no text between consecutive delimiters, split returns an empty string.

[newStr,match] = split(str,["and",","," "])
newStr = 7x1 string
    "bacon"
    ""
    "lettuce"
    ""
    ""
    ""
    "tomato"

match = 6x1 string
    ","
    " "
    ","
    " "
    "and"
    " "

Join newStr and match back together with the join function.

originalStr = join(newStr,match)
originalStr = 
"bacon, lettuce, and tomato"

Input Arguments

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Input text, specified as a string array, character vector, or cell array of character vectors.

Delimiting substrings, specified as one of the following:

  • String array

  • Character vector

  • Cell array of character vectors

  • pattern array (since R2020b)

The substrings specified in delimiter do not appear in the output newStr.

Specify multiple delimiters in a string array, cell array of character vectors, or pattern array. The split function splits str on the elements of delimiter. The order in which delimiters appear in delimiter does not matter unless multiple delimiters begin a match at the same character in str. In that case, the split function splits on the first matching delimiter in delimiter.

Example: split(str,{' ',',','--'}) splits str on spaces, commas, and pairs of consecutive dashes.

Dimension along which to split strings, specified as a positive integer. If dim is not specified, then the default is the last array dimension with a size that does not equal 1.

Output Arguments

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Substrings split out of original array, returned as a string array or cell array of character vectors. If the input array str is a string array, then so is newStr. Otherwise, newStr is a cell array of character vectors.

Identified delimiters, returned as a string array or cell array of character vectors. If the input array str is a string array, then so is match. Otherwise, match is a cell array of character vectors.

match always contains one fewer element than output newStr contains.

Extended Capabilities

Introduced in R2016b