# Size mismatching using "find" command

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Matteo Migone on 12 Aug 2022
Commented: Voss on 14 Aug 2022
Hi everyone,
I'm experiencing some issues using the find command inside a for loop. I have a 28x230 matrix (mean_GMT_min_mean_ref); of every row, I want to detect the first time the value 2, when present, is reached. That is the problem. Given this code
for i=1:length(FileList)
y(i,1) = find((floor(mean_GMT_min_mean_ref(i,:))==2),1,'first');
value_2(i,1) = mean_GMT_min_mean_ref(i,y(i));
year_gwl_2(i,1) = x(y(i,1));
end
I get the error "Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-0." This because e.g. the second line of the matrix (and others) is made of values all < 2. I would just like, in the case that value isn't reached, to get a NaN in the column vector (y, value_2 and year_gwl_2 are all 28x1 vectors), instead of quitting the for loop with that annoying error.
Can anyone help me with this? Thanks in advance, Matteo

Voss on 12 Aug 2022
for i=1:length(FileList)
idx = find((floor(mean_GMT_min_mean_ref(i,:))==2),1,'first');
if isempty(idx)
y(i,1) = NaN;
value_2(i,1) = NaN;
year_gwl_2(i,1) = NaN;
else
y(i,1) = idx;
value_2(i,1) = mean_GMT_min_mean_ref(i,y(i));
year_gwl_2(i,1) = x(y(i,1));
end
end
##### 2 CommentsShowHide 1 older comment
Voss on 14 Aug 2022
You're welcome!

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