splitvars

Split multicolumn variables in table or timetable

Syntax

T2 = splitvars(T1)

T2 = splitvars(T1,vars)

T2 = splitvars(T1,vars,'NewVariableNames',newNames)

Description

T2 = splitvars(T1) splits all multicolumn variables in T1 so that they are single-column variables in T2. All single-column variables from T1 are unaltered.

• If a variable in T1 has multiple columns, then splitvars makes unique names for the new variables in T2 from the name of the original variable in T1.

• If a variable in T1 is a table itself, then splitvars uses the names of its variables (and, if necessary, the name of that table) to make unique names for the new variables in T2.

To merge variables into one multicolumn variable, use the mergevars function.

T2 = splitvars(T1,vars) splits only the table variables specified by vars. You can specify variables by name, by position, or using logical indices.

T2 = splitvars(T1,vars,'NewVariableNames',newNames) assigns new names to the designated variables that are split out of T1 and copied to T2.

Examples

Split Variables

Create a table from workspace variables. Some of the variables are matrices with multiple columns.

A = (1:3)';
B = [5 11 12; 20 30 50; 0.1 3.4 5.9]';
C = {'a','XX';'b','YY';'c','ZZ'};
D = [128 256 512]';
T1 = table(A,B,C,D)

T1=3×4 table
    A           B                   C            D 
    _    ________________    _______________    ___

    1     5     20    0.1    {'a'}    {'XX'}    128
    2    11     30    3.4    {'b'}    {'YY'}    256
    3    12     50    5.9    {'c'}    {'ZZ'}    512

Split the variables B and C. All variables in the output table have one column.

T2 = splitvars(T1)

T2=3×7 table
    A    B_1    B_2    B_3     C_1      C_2       D 
    _    ___    ___    ___    _____    ______    ___

    1     5     20     0.1    {'a'}    {'XX'}    128
    2    11     30     3.4    {'b'}    {'YY'}    256
    3    12     50     5.9    {'c'}    {'ZZ'}    512

Specify Variable

Create a table that contains tables, using arrays of data from the patients.mat file. Display the first three rows.

load patients
Personal_Data = table(Gender,Age);
BMI_Data = table(Height,Weight);
BloodPressure = table(Systolic,Diastolic);
T1 = table(LastName,Personal_Data,BMI_Data,BloodPressure);
head(T1,3)

      LastName        Personal_Data          BMI_Data            BloodPressure    
    ____________    _________________    ________________    _____________________

                      Gender      Age    Height    Weight    Systolic    Diastolic
                    __________    ___    ______    ______    ________    _________
                                                                                  
    {'Smith'   }    {'Male'  }    38       71       176        124          93    
    {'Johnson' }    {'Male'  }    43       69       163        109          77    
    {'Williams'}    {'Female'}    38       64       131        125          83    

Specify BloodPressure as the variable to split.

T2 = splitvars(T1,'BloodPressure');
head(T2,3)

      LastName        Personal_Data          BMI_Data        Systolic    Diastolic
    ____________    _________________    ________________    ________    _________

                      Gender      Age    Height    Weight                         
                    __________    ___    ______    ______                         
                                                                                  
    {'Smith'   }    {'Male'  }    38       71       176        124          93    
    {'Johnson' }    {'Male'  }    43       69       163        109          77    
    {'Williams'}    {'Female'}    38       64       131        125          83    

To specify multiple variables by name, use a cell array of character vectors.

T3 = splitvars(T1,{'BMI_Data','BloodPressure'});
head(T3,3)

      LastName        Personal_Data      Height    Weight    Systolic    Diastolic
    ____________    _________________    ______    ______    ________    _________

                      Gender      Age                                             
                    __________    ___                                             
                                                                                  
    {'Smith'   }    {'Male'  }    38       71       176        124          93    
    {'Johnson' }    {'Male'  }    43       69       163        109          77    
    {'Williams'}    {'Female'}    38       64       131        125          83    

To specify variables by position, use a numeric array.

T4 = splitvars(T1,[2 4]);
head(T4,3)

      LastName        Gender      Age        BMI_Data        Systolic    Diastolic
    ____________    __________    ___    ________________    ________    _________

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

New Names for Split Variables

Create a table that contains multi-column variables, using data from the patients.mat file. Display the first three rows.

load patients
Personal_Data = [Age,Height,Weight];
BloodPressure = [Systolic,Diastolic];
T1 = table(LastName,Gender,Personal_Data,BloodPressure);
head(T1,3)

      LastName        Gender       Personal_Data      BloodPressure
    ____________    __________    ________________    _____________

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

Split BloodPressure and specify new names for the new variables in the output table.

T2 = splitvars(T1,'BloodPressure','NewVariableNames',{'Systolic','Diastolic'});
head(T2,3)

      LastName        Gender       Personal_Data      Systolic    Diastolic
    ____________    __________    ________________    ________    _________

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

Split both BMI_Data and BloodPressure. For each variable being split, you must provide a cell array with the correct number of new names.

T3 = splitvars(T1,{'Personal_Data','BloodPressure'},...
     'NewVariableNames',{{'Age','Height','Weight'},{'Systolic','Diastolic'}});
head(T3,3)

      LastName        Gender      Age    Height    Weight    Systolic    Diastolic
    ____________    __________    ___    ______    ______    ________    _________

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

Input Arguments

T1 — Input table

table | timetable

Input table, specified as a table or timetable.

vars — Variables in input table

string array | character vector | cell array of character vectors | pattern scalar | numeric array | logical array

Variables in the input table, specified as a string array, character vector, cell array of character vectors, pattern scalar, numeric array, or logical array.

newNames — Names of split variables

cell array of character vectors | string array

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

Extended Capabilities

Tall Arrays

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

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

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• The vars input argument does not support pattern expressions.

• The value of the 'NewVariableNames' name-value argument must be constant.

• The variables that are split cannot have a variable number of columns.

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.

Version History

Introduced in R2018a