Using string variable names for dot indexing

Hello,

I have a list of the varaible names:

varnames = {'rsrp_nr' 'sinr_nr' 'bler_dl_nr' 'bler_ul_nr' 'mcs_dl_nr' 'mcs_ul_nr' 'layers_dl_nr' 'layers_ul_nr' 'tp_pdsch_dl_nr' 'tp_pusch_ul_nr'};

And i would like to use this list to call a rows by the name f.a.:

rr=2

my_files{1,1}.varnames(rr)

I woudl like the code to process this as:

my_files{1,1}.sinr_nr

For now I am getting an error:

Error using tabular/dotParenReference

Unrecognized table variable name 'varnames'.

Thanks!

[Stephen23]

https://www.mathworks.com/help/matlab/matlab_prog/access-data-in-a-table.html

Answer 1

[Star Strider]

That approach can work, however it is necessary to put the variable name from the cell array in parentheses —

varnames = {'rsrp_nr' 'sinr_nr' 'bler_dl_nr' 'bler_ul_nr' 'mcs_dl_nr' 'mcs_ul_nr' 'layers_dl_nr' 'layers_ul_nr' 'tp_pdsch_dl_nr' 'tp_pusch_ul_nr'}; 

Test = array2table(randn(5,numel(varnames)), 'VariableNames',varnames)

Test = 5×10 table
    rsrp_nr      sinr_nr     bler_dl_nr    bler_ul_nr    mcs_dl_nr    mcs_ul_nr    layers_dl_nr    layers_ul_nr    tp_pdsch_dl_nr    tp_pusch_ul_nr
    ________    _________    __________    __________    _________    _________    ____________    ____________    ______________    ______________

     0.53165      -1.4146      0.15515         1.656      -1.7371       1.3253         1.6272        -0.44658          0.97248           0.87074   
    0.041848       2.0438      0.15903      -0.51318      -1.0633       1.0485        -1.7061        -0.52948          -1.2473          -0.39379   
     0.51137     -0.50428      0.22443       0.79484      0.76808      0.65757       -0.16261        -0.86027         -0.86237           -2.0298   
     -1.0916    -0.024071      0.85436       0.40742       0.4719     -0.53527        0.64941         0.10239          0.76209          -0.10233   
      1.0462      -1.4834     -0.36448      -0.24396     -0.16983      0.93012       -0.30279         0.40905           1.4175           0.62576   

rr = 2;
vn = varnames(rr)

vn = 1×1 cell array
    {'sinr_nr'}

GetColumn = Test.(varnames{rr})

GetColumn = 5×1

-1.4146 2.0438 -0.5043 -0.0241 -1.4834

That also works if the variable name is not a normal MATLAB variable name (for example containing a space or other special characters).

.

Answer 2

[Rik]

You're missing parentheses:

varnames = {'rsrp_nr' 'sinr_nr'};
T=table(pi,2*pi,VariableName={'rsrp_nr' 'sinr_nr'})

T = 1×2 table
    rsrp_nr    sinr_nr
    _______    _______

    3.1416     6.2832 

T.(varnames{2})

ans = 6.2832