Mean of array columns with condition

I have an array of which I need the mean of each column (X). Additionally, I have a logical array of which rows meet a condition and should be included in the mean (Y).

Naturally, the mean function in MATLAB calculates each column mean, but when I insert the logical vector for the row selection, the mean is calculated for the whole array. How do I fix this for computing the mean of each column in X for the valid indices of Y?

When entering

means_active = mean(X(Y), :);

I get the error 'Reference to a cleared variable mean.', though I don't want to use any variable 'mean' but the built-in function 'mean'.

[KALYAN ACHARJYA]

Please illustrate with example, rather than texts?

[Mariella Dreißig]

I already copied the line of code I'm talking about, I don't know how to illustrate more.

means_active = mean(X(Y(:,1) < cutoff), :);    

[Mariella Dreißig]

I found a workaround though, thanks :)

Answer 1

[Philippe Lebel]

I tested my solution with these matrices:

a = rand(6,3)
B=[1;0;1;1;0;1];
means_active = mean(a(logical(B)),2);

seems to work for me. (i was forced to cast B as logical because i manually declared the values inside the list as integers)