Finding maximum value and returning variable name of the column

Hello all!

Data:

A = [1;2;3;4];
B = [5;4;1;2];
C = [2;3;2;5];
T=table(A,B,C);

I would like to have a function that would check each row for the largest number and return the name of the collum where the max value was found. In this case, it should return: B,B,A,C

The table is just an example, I don't mind using cell arrays, tables or any other way how to work with the data.

Additional points: How to make sure that the function would return the character closest to A in case the largest numbers would occur multiple times in the same row?

Answer 1

[Davide Masiello]

clear,clc

A = [1;2;3;4];
B = [5;4;1;2];
C = [2;3;2;5];
T=table(A,B,C);

[maxval,idx] = max(table2array(T),[],2);
T.Properties.VariableNames(idx)

ans = 1×4 cell array
    {'B'}    {'B'}    {'A'}    {'C'}

Regarding the additional point question, I think the max function will do that by default (i.e. it will return the first max value it finds on a specific row). Check this for instance:

clear,clc

A = [1;4;3;4];
B = [5;4;1;2];
C = [2;3;2;5];
T=table(A,B,C);
[maxval,idx] = max(table2array(T),[],2);
T.Properties.VariableNames(idx)

ans = 1×4 cell array
    {'B'}    {'A'}    {'A'}    {'C'}

Answer 2

[Cris LaPierre]

Look into finding the max along the second dimension, and have it return the loacation of the max.

• M = max(A,[],dim)
• [M,I] = max(___)

However, max does not work with tables, so you will need to turn your table into an Array using table2array.

You can create a vector containting your table variable names. Use the index from max to extract the corresponding variable names.

varNames = T.Properties.VariableNames