# emptying each row of matrix of a in a loop then uses respective matrices produced from it to get a certain value

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JL on 22 Aug 2019
Commented: JL on 27 Aug 2019
I have a matrix, a
a = [1 2;
1 3;
1 5;
1 7;
1 8;];
and this matrix a, is emptied in each row per loop until the last one using this code from Matt J
a0=a;
for i=1:size(a,1)
a=a0;
a(i,:)=[],
end
which result in:
a = [1 3;
1 5;
1 7;
1 8;];
a = [1 2;
1 5;
1 7;
1 8;];
a = [1 2;
1 3;
1 7;
1 8;];
a = [1 2;
1 3;
1 5;
1 8;];
a = [1 2;
1 3;
1 5;
1 7;];
can I create another loop to calculate a certain value, w, from the results from each loop beginning with the orginal until the last one. After each loop answer value, w, is tabulated in matrix b
b = [w
w
w
w
w
w]
there 6 values of w since we consider the orginal a
David Hill on 22 Aug 2019
preallowcating array b = zeros(size(a,1)-1,2,size(a,1));
and having the following in the loop
b(:,:,i)=a;

Matt J on 22 Aug 2019
Edited: Matt J on 22 Aug 2019
Why not as follows,
b=nan(size(a,1),1); %pre-allocate
for i=1:size(a,1)
tmp=a;
tmp(i,:)=[],
b(i)=max(tmp(:))-min(tmp(:)); %example derived quantity
end
JL on 27 Aug 2019
Thank you!

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