How can I find the maximum value and time array in MATLAB?

Hi

Suppose I have a matrix that has time in column one and other values in column two a = [1 2 ; 4 5 ; 7 8 ; 6 11 ; 4 3 ].

What is the function returning the maximum value in column two and at what time from column one?

For example, the maximum value in the second column of a matrix is 11 and at time equal 6.

Your help would be appreciated

Thanks

Answer 1

[Rik]

Use the second output of max:

a = [1 2 ; 4 5  ; 7 8 ; 6 11 ; 4 3 ];
[val,ind]=max(a(:,2));
time_val=a(ind,1);

[Abdulaziz Gheit]

Thanks for your response Rik

But what if I have one time column and other 500 columns for another data.

I need to obtain the maximum value from each data column and at which time it happened.

Thank you

[Rik]

Have you read the documentation page for the max function to see what syntax options are available?

[Rik]

Answer posted as comment by Abdulaziz Gheit:

Of course I did. But none of them worked for me. I believe it's more than one function to be used.

I'm a new user to Matlab and I managed to obtain only the indx but not the value itself.

Sure it is simple to be done but not for someone who just starts using Matlab.

Thanks for your attention.

[Rik]

You should probably convert the row-indices to linear indices:

A=rand(4,10);
col_idx=[1 3 6 4];%find with max
row_idx=1:4;%columns searched with max
ind=sub2ind(size(A),row_idx,col_idx);
vals=A(ind)