Replacing multiple columns elegantly with a vector

I am looking for an elegant and simple way to replace a some columns in a matrix (specified by a logical array) with a given column vector, e.g:

M = magic(5);
    
replace_column = boolean([1 0 0 1 0]); %replace the 1st and 4th column
replace_with = [5;5;5;5;5]; %column vector that the targeted columns should be replaced with

I now want to replace the columns corresponding to the entries of replace_column equal to 1 with the vector specified in replace_with.

I do not want to use a for-loop here, because I think there is a simple solution to this. However, using

M(:,replace_column) = replace_with;

results in an error:

Unable to perform assignment because the size of the left side is 5-by-2 and the size of the right side is 5-by-1.

Do you have an idea how to solve this?

Answer 1

[Fangjun Jiang]

You want to replace two columns but only provided one column of data. Provide the matching data.

M(:,replace_column) =repmat(5,5,2)

[Gabriel Seidl]

thanks, this works.