# replace numbers in the matrix

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EK on 18 Dec 2022
Edited: Image Analyst on 19 Dec 2022
Hello,
I have a matrix of 6 columns (an example attached here) that are: trials, stimulus IDs, Hit, Miss, CR, FA.
Hit, Miss, CR, FA columns are coded as a 0 and 1. Sometimes the correspondent rows in FA and CR column are coded with 1. I need to correct this and everywhere when FA row = 1 replace correspondent row im CR column with 0
Can anyone help with this?
Torsten on 18 Dec 2022
Better you immediately give the matrix you expect as result in the above case to avoid unnecessary attempts.

Image Analyst on 18 Dec 2022
Edited: Image Analyst on 18 Dec 2022
Try this:
% Colulmns are: trials, stimulus IDs, Hit, Miss, CR, FA.
% Find where last column, FA, is 1
rows1 = data(:, end) == 1;
% "replace correspondent row im CR column from with 0 "
% In English: "replace the element in the corresponding row in the CR column with 0"
data(rows1, 5) = 0
data = 19×6
1 4 0 0 1 0 2 3 1 0 0 0 3 3 1 0 0 0 4 4 0 0 1 0 5 3 0 1 0 0 6 4 0 0 0 1 7 3 0 1 0 0 8 4 0 0 1 0 9 4 0 0 1 0 10 3 0 1 0 0
EK on 18 Dec 2022
yes it is only in case if both CR and FA are equal 1
Image Analyst on 19 Dec 2022
Edited: Image Analyst on 19 Dec 2022
Oh, I thought that "Sometimes the correspondent rows in FA and CR column are coded with 1" but that you only wanted to set CR to zero when "when FA row = 1". But if what you really meant was "when FA row = 1 AND when CR row = 1", then you can make the obvious change:
% Colulmns are: trials, stimulus IDs, Hit, Miss, CR, FA.
% Find where 5th column is 1 and the last column, FA, is 1.
% That is, both 1 in the same row.
rows1 = (data(:, 5) == 1) & (data(:, end) == 1);
% "replace correspondent row im CR column from with 0 "
% In English: "replace the element in the corresponding row in the CR column with 0"
data(rows1, 5) = 0

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