Converting matrix entries satisfying a threshold condition.
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Paul Fishback
on 29 Jan 2015
Edited: Zakaria Abdelli
on 21 Oct 2022
I have a matrix of numeric entries and wish to convert each entry above a specified threshold to one and all other entries to zero. This has to be an elegant way to do this without a "for" loop. Perhaps using the "find" command in some manner?
Accepted Answer
Star Strider
on 29 Jan 2015
There are likely a number of ways.
One approach:
M = magic(6);
Mm = mean(M(:));
M(M>Mm) = 1;
M(M~=1) = 0;
It sets all the entries greater than the mean to 1, and then uses that result to set the rest to 0.
4 Comments
Star Strider
on 7 Mar 2020
@Tamir Eisenstein —
M = randi(99, 10); % Create Matrix
Msort = sort(M(:),'descend'); % Sorted Vector
Threshold = Msort(fix(numel(M)*0.2)); % Find Top 20% Value
Out = zeros(size(M))~=0; % Create Logical Matrix
Out(M >= Threshold) = 1; % Desired Result
Zakaria Abdelli
on 21 Oct 2022
Edited: Zakaria Abdelli
on 21 Oct 2022
how do i do it with 3 and others 0 can you give me a hint pleas im just a newbee???
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