How to Find Max and Min of a Matrix Column in Matlab?

[joanne34567]

Hi, I want to find the maximum and minimum values of a column in a matrix.
I have a 4 column, 100 row matrix and need the minimum and maximum value in the 4th column. I need this to be extracted along with the other values of that row. Can anyone help?

 

[Kreizhn]

Try "help max" and "help min."

[Y,I] = MAX(X,[],DIM)

Y is the max value of X taken along the dim- dimension at the index I.

For your case in particular, let X be your matrix. To tell MATLAB to look at the 4th column only you would write X(:,4) which says "X at all rows and the 4th column." Then
[Y,I] = max(X(:,4))
will give you the maximum element Y and the index I in which that occurs. Now the row that corresponds to that maximum is the I-th row. To get the I-th row, write X(I,:) which say "X at the I-th row and all columns"

Hope that helps.