addvars

Add variables to table or timetable

Syntax

T2 = addvars(T1,var1,...,varN)

T2 = addvars(T1,var1,...,varN,'After',location)

T2 = addvars(T1,var1,...,varN,'Before',location)

T2 = addvars(___,'NewVariableNames',newNames)

Description

T2 = addvars(T1,var1,...,varN) adds the arrays specified by var1,…,varN as new variables to the right of the last variable in T1. The input arrays var1,…,varN can be arrays having any data type, tables, and timetables. All input arguments must have the same number of rows as T1.

For example, to add a column vector named A after the last variable in T1, use T2 = addvars(T1,A).

T2 = addvars(T1,var1,...,varN,'After',location) inserts the variables to the right of the table variable indicated by location. You can specify location as a variable name, or a numeric or logical index.

For example, to insert a column vector named A after table variable var2, use T2 = addvars(T1,A,'After','var2').

T2 = addvars(T1,var1,...,varN,'Before',location) inserts the variables to the left of the table variable indicated by location.

For example, to insert a column vector named A before table variable var3, use T2 = addvars(T1,A,'Before','var3').

T2 = addvars(___,'NewVariableNames',newNames) renames the added variables in T2 using the names specified by newNames. The number of names in newNames must be the same as the number of added variables. You can use this syntax with any of the input arguments of the previous syntaxes.

Examples

Add Variables

Create a table. Then add variables from the workspace to the table.

Load arrays from the patients.mat file. Create a table that contains the names, ages, heights, and weights of patients. Then display the first three rows.

load patients
T1 = table(LastName,Age,Height,Weight);
head(T1,3)

      LastName      Age    Height    Weight
    ____________    ___    ______    ______

    {'Smith'   }    38       71       176  
    {'Johnson' }    43       69       163  
    {'Williams'}    38       64       131  

Add the workspace variables, Gender and Smoker, to the table.

T2 = addvars(T1,Gender,Smoker);
head(T2,3)

      LastName      Age    Height    Weight      Gender      Smoker
    ____________    ___    ______    ______    __________    ______

    {'Smith'   }    38       71       176      {'Male'  }    true  
    {'Johnson' }    43       69       163      {'Male'  }    false 
    {'Williams'}    38       64       131      {'Female'}    false 

Insert Variables at Specified Locations

Create a table. Then insert variables before and after specified locations in the table.

Load arrays from the patients.mat file. Create a table that contains the names and genders of patients. Then display the first three rows.

load patients
T1 = table(LastName,Gender);
head(T1,3)

      LastName        Gender  
    ____________    __________

    {'Smith'   }    {'Male'  }
    {'Johnson' }    {'Male'  }
    {'Williams'}    {'Female'}

Insert the workspace variable, Age, before the table variable, Gender. To refer to a table variable by name, specify its name as a character vector.

T2 = addvars(T1,Age,'Before','Gender');
head(T2,3)

      LastName      Age      Gender  
    ____________    ___    __________

    {'Smith'   }    38     {'Male'  }
    {'Johnson' }    43     {'Male'  }
    {'Williams'}    38     {'Female'}

Insert more variables after Age. Since Age is a table variable in T2, specify its name as a character vector.

T3 = addvars(T2,Height,Weight,'After','Age');
head(T3,3)

      LastName      Age    Height    Weight      Gender  
    ____________    ___    ______    ______    __________

    {'Smith'   }    38       71       176      {'Male'  }
    {'Johnson' }    43       69       163      {'Male'  }
    {'Williams'}    38       64       131      {'Female'}

Insert Smoker after the first table variable. You can specify variables by position in the table instead of by name.

T4 = addvars(T3,Smoker,'After',1);
head(T4,3)

      LastName      Smoker    Age    Height    Weight      Gender  
    ____________    ______    ___    ______    ______    __________

    {'Smith'   }    true      38       71       176      {'Male'  }
    {'Johnson' }    false     43       69       163      {'Male'  }
    {'Williams'}    false     38       64       131      {'Female'}

Rename Variables

Create a table. Add variables and give them new names in the table.

First, create a table from workspace variables.

load patients
T1 = table(LastName,Age,Gender,Smoker);
head(T1,3)

      LastName      Age      Gender      Smoker
    ____________    ___    __________    ______

    {'Smith'   }    38     {'Male'  }    true  
    {'Johnson' }    43     {'Male'  }    false 
    {'Williams'}    38     {'Female'}    false 

Combine Diastolic and Systolic into one matrix with two columns. Name the new table variable BloodPressure.

T2 = addvars(T1,[Diastolic Systolic],'NewVariableNames','BloodPressure');
head(T2,3)

      LastName      Age      Gender      Smoker    BloodPressure
    ____________    ___    __________    ______    _____________

    {'Smith'   }    38     {'Male'  }    true        93    124  
    {'Johnson' }    43     {'Male'  }    false       77    109  
    {'Williams'}    38     {'Female'}    false       83    125  

Add Height and Weight as new table variables. Rename them Inches and Pounds.

T3 = addvars(T2,Height,Weight,'Before','Smoker','NewVariableNames',{'Inches','Pounds'});
head(T3,3)

      LastName      Age      Gender      Inches    Pounds    Smoker    BloodPressure
    ____________    ___    __________    ______    ______    ______    _____________

    {'Smith'   }    38     {'Male'  }      71       176      true        93    124  
    {'Johnson' }    43     {'Male'  }      69       163      false       77    109  
    {'Williams'}    38     {'Female'}      64       131      false       83    125  

Input Arguments

T1 — Input table

table | timetable

Input table, specified as a table or timetable.

var1,...,varN — Variables to add to output table

arrays, tables, and timetables

Variables to add to the output table, specified as arrays, tables, and timetables. The variables specified by var1,...,varN all must have the same number of rows as the input table T1.

Example: T2 = addvars(T1,A) inserts the workspace variables A to the right of the last table variable.

Example: T2 = addvars(T1,X,Y,Z) inserts the workspace variables X, Y, and Z.

location — Location to insert added variables

character vector | string scalar | integer | logical array

Location to insert added variables, specified as a character vector, string scalar, integer, or logical array.

• If location is a character vector or string scalar, then it is the name of a variable in the input table T1.

• If location is the integer n, then it specifies the nth variable in T1.

• If location is a logical array, whose nth element is 1 (true), then it specifies the nth variable in T1. All other elements of location must be 0 (false).

Example: T2 = addvars(T1,Latitude,'Before','Longitude') insert the workspace variable Latitude to the left of the table variable named Longitude.

Example: T2 = addvars(T1,Y,Z,'After','X') inserts the workspace variables Y and Z to the right of the table variable named X.

newNames — Names of added variables

character vector | cell array of character vectors | string array

Names of the added variables, specified as a character vector, cell array of character vectors, or string array.

Example: T2 = addvars(T1,lat,lon,'NewVariableNames',{'Latitude','Longitude'}) inserts the workspace variables lat and lon and names the corresponding table variables 'Latitude' and 'Longitude'.

Limitations

• Use single quotes for the input names 'Before', 'After', and 'NewVariableNames'. To avoid confusion with variable inputs, do not use double-quoted string scalars (such as "Before") for these names.

Extended Capabilities

Tall Arrays

Calculate with arrays that have more rows than fit in memory.

The addvars function fully supports tall arrays. For more information, see Tall Arrays.

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

This function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced in R2018a