Find Max values in each row

Hi everyone, I have a Matlab question and I'm having some issues...

I have data (please see the data above) known as A1. I have 3 rows but row one is just the x-axis. I want to extract the max value in each row (rows 2 and 3) as well as the associated x-axis (row 1) value for each max value. The code I'm using is below:

[maxA1, index] = max(A1,[],2);

In this case, maxA1 rightfully gives me 1.6 and 2.3 as the max values for rows 2 an 3 respectfully. The index value is giving me just the column numbers (i.e., 4 or D in the case of excel and 3 or C in the case of excel). In reality, I am not interested in the column #s, I was hoping to get the corresponding x-axis values in row 1 instead (in this case, 500 and 400). I wouldn't mind to get the index/column #s as well but what I really need is the x-axis values.

Please is there a way or any suggestion on how the code can be modifie to give me the max values in rows 2 and 3 as well as their corresponding x-axis values (which is in row 1) and possibly the index/column number as well?

Thank you!

Answer 1

[Voss]

A1 = [ ...
    200 300 400 500 600; ...
    1.2 1.3 1.4 1.6 1.2; ...
    1.5 1.9 2.3 1.5 1.2];

Use the index you get to index into the first row of A1:

[maxA1, index] = max(A1,[],2)

maxA1 = 3×1

600.0000 1.6000 2.3000

index = 3×1

5 4 3

maxX = A1(1,index)

maxX = 1×3

600 500 400

(Same as above, except using only rows 2 through the end of A1:)

[maxA1, index] = max(A1(2:end,:),[],2)

maxA1 = 2×1

1.6000 2.3000

index = 2×1

4 3

maxX = A1(1,index)

maxX = 1×2

500 400

[Learning]

Thank you!!

[Voss]

You're welcome!