# Change certain values in a matrix

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Nikolas Spiliopoulos on 29 Dec 2021
Answered: Nihal on 15 Nov 2023
Hi all I jhave a matrix A
A=[1 1 0 0 1 1 1 0; 0 0 1 1 1 1 0 0; 1 1 0 0 1 1 0 1; 1 1 1 1 1 1 1 1; 1 1 1 1 1 1 1 1]
I would like to "correct" its columns like this:
when I have a column where the sequence "0 1 0" appears I want to be changed to "0 0 0"
AND
when I have a column where the sequence "1 0 1" appears I want to be changed to "1 1 1"
So I have finaly the matrix B
B=[1 1 0 0 1 1 1 0; 1 1 0 0 1 1 0 0; 1 1 0 0 1 1 0 1; 1 1 1 1 1 1 1 1; 1 1 1 1 1 1 1 1]
I would like to use it for a larger matrix under this concept.
Do you know how to do it?
Torsten on 29 Dec 2021
Edited: Torsten on 29 Dec 2021
I would say you have to define another rule.
Nikolas Spiliopoulos on 29 Dec 2021
ok thanks!

Nihal on 15 Nov 2023
Hi Nikolas,
I have understood that you are looking to replace specific patterns in a column vector. To perform the action you can try the below code which will yeild the desired result:
A=[1 1 0 0 1 1 1 0; 0 0 1 1 1 1 0 0; 1 1 0 0 1 1 0 1; 1 1 1 1 1 1 1 1; 1 1 1 1 1 1 1 1];
B=[1 1 0 0 1 1 1 0; 1 1 0 0 1 1 0 0; 1 1 0 0 1 1 0 1; 1 1 1 1 1 1 1 1; 1 1 1 1 1 1 1 1];
X=A;
% row vector format
pattern1 = [0 1 0];
pattern2 = [1 0 1 1];
X = applyFilter(A,pattern1,[0 0 0]);
X = applyFilter(X,pattern2,[1 1 1 1]);
isequal(X,B) % Check if X is equal to B
X % Display the corrected matrix X
B % Display the desired matrix B
function X = applyFilter(A,pattern,replaceWith)
X=A;
patternSize = size(pattern,2);
for row = 1:size(A,1)- patternSize
for col = 1:size(A, 2)
isequal(A(row:row+patternSize-1, col), pattern' ); % Check if the pattern matches the current submatrix
if isequal(A(row:row+patternSize-1, col), pattern' )
X(row:row+patternSize-1, col)= replaceWith'; % Replace the submatrix with the specified values
end
end
end
end
Feel free to modify the code according your usecase. I hope it helped in resolving your issue.