How to change an entire column.

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Anton Mulder
Anton Mulder on 29 Apr 2013
Hi,
I have a matrix with a dimension of 10x640. The matrix is filled with ones and zeros. If there is a zero in one of columns, I want the entire column to be zeros. How can I do this?
Example:
[[1,0,1];[1,1,1]]
Output should be:
[[1,0,1];[1,0,1]]

Accepted Answer

Iman Ansari
Iman Ansari on 29 Apr 2013
A = randi(10,[10 640])-1;
B = A;
B(:,sum(A==0)>0)=0;
  1 Comment
Jan
Jan on 29 Apr 2013
any(A, 2) is faster than sum(A==0)>0.

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More Answers (1)

Image Analyst
Image Analyst on 29 Apr 2013
Try this:
% Make sample data.
A = ones(10, 640);
% Stick a zero in columns 3, and 5.
A(9, 3) = 0;
A(8, 5) = 0
% Now that we have some sample data, do what Anton wants.
% Find out which columns have zeros in them
columnsWithZeros = any(~A); % Assumes A is only 0's and 1's.
A(:, columnsWithZeros) = 0; % Set whole column(s) to zero.
  1 Comment
Image Analyst
Image Analyst on 29 Apr 2013
If you want a terse "one-liner" you can do this:
A(:, any(~A)) = 0;

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