How to delete/retain variables (columns) from a table based on sections of the variables name

Question

Robert 2018-1-12

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https://ww2.mathworks.cn/matlabcentral/answers/376797-how-to-delete-retain-variables-columns-from-a-table-based-on-sections-of-the-variables-name

评论： Robert 2018-1-12

Hello,

Wondering if anyone knows how to delete/retain variables (columns) from a table based on portions of the variables name?

This is a simple example, real data has more than 30000 variables (columns) with combinations of names and other information.

 AA_001_AMER_USA     AA_002_AMER_USA     AA_001_AMER_CAN     BB_001_AMER_USA    BB_002_AMER_CAN

How to delete only variables with name section 'USA'

How to delete only variables with name section '001' & 'USA'

How to retain only variables with name section= 'USA'

How to retain only variables with name section= '001' & 'USA'

Thanks!

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Answer 1

per isakson 2018-1-12

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/376797-how-to-delete-retain-variables-columns-from-a-table-based-on-sections-of-the-variables-name#answer_299819

编辑：per isakson 2018-1-12

One way

%%Sample table   
    tbl = array2table( magic(5) );   
    tbl.Properties.VariableNames =              ...
        { 'A_001_AMER_USA' , 'AA_002_AMER_USA'  ...  
        , 'AA_001_AMER_CAN', 'BB_001_AMER_USA'  ...
        , 'BB_002_AMER_CAN'                     };

How to retain only variables with name section 'USA'

    cac = regexp( tbl.Properties.VariableNames, '^.+_USA$', 'match' );
    T01 = tbl( :, cat(2,cac{:}) );
%%How to retain only variables with name section= '001' & 'USA'
    cac = regexp( tbl.Properties.VariableNames, '^[^_]+_001_[^_]+_USA$', 'match' );
    T02 = tbl( :, cat(2,cac{:}) );

How to delete only variables with name section 'USA'

    cac = regexp( tbl.Properties.VariableNames, '^.+_USA$', 'match' );
    T03 = tbl;
    T03( :, cat(2,cac{:}) ) = [];
%%How to delete only variables with name section '001' & 'USA'
    cac = regexp( tbl.Properties.VariableNames, '^[^_]+_001_[^_]+_USA$', 'match' );
    T04 = tbl;
    T04( :, cat(2,cac{:}) ) = [];

and a variant, which I guess is faster

How to retain only variables with name section 'USA'

    cac = regexp( tbl.Properties.VariableNames, '^.+_USA$' );
    T01 = tbl( :, not( cellfun( @isempty, cac ) ) );
%%How to retain only variables with name section= '001' & 'USA'
    cac = regexp( tbl.Properties.VariableNames, '^[^_]+_001_[^_]+_USA$' );
    T02 = tbl( :, not( cellfun( @isempty, cac ) ) );

How to delete only variables with name section 'USA'

    cac = regexp( tbl.Properties.VariableNames, '^.+_USA$' );
    T03 = tbl( :, cellfun( @isempty, cac ) );
%%How to delete only variables with name section '001' & 'USA'
    cac = regexp( tbl.Properties.VariableNames, '^[^_]+_001_[^_]+_USA$' );
    T04 = tbl( :, cellfun( @isempty, cac ) );