# creating loop with two variables

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sermet on 7 Dec 2017
Answered: Jan on 7 Dec 2017
For example;
a=0:2:10;
b=0:2:6;
% number of elements of a is always bigger than b
I need to create for loop as below;
result(1)=a(1)-b(1);
result(2)=a(2)-b(2);
result(3)=a(3)-b(3);
result(4)=a(4)-b(4);
result(5)=a(5)-b(4);
result(6)=a(6)-b(4);
Since a and b variables' number isn't constant for each problem. How can I create this loop for working properly with arbitrary numbers of a and b?

Birdman on 7 Dec 2017
Edited: Birdman on 7 Dec 2017
for i=1:max(numel(a),numel(b))
if(i>=min(numel(a),numel(b)))
result(i)=a(i)-b(min(numel(a),numel(b)));
else
result(i)=a(i)-b(i);
end
end
KL on 7 Dec 2017
You could call numel, outside the loop and store its output in a variable (after finding min and max) and only use this variable inside the loop.
Now, you're calling min and numel so many times (sometimes even twice within the same iteration).

Stephen23 on 7 Dec 2017
Edited: Stephen23 on 7 Dec 2017
Why waste time writing an ugly loop? Here is a simpler solution in just two lines:
>> a = 0:2:10;
>> b = 0:2:6;
>> v = 1:max(numel(a),numel(b));
>> a(min(v,end))-b(min(end,v))
ans =
0 0 0 0 2 4

Jan on 7 Dec 2017
% number of elements of a is always bigger than b
This was not considered in the other suggestions. Another solution:
a = 0:2:10;
b = 0:2:6;
result = a - b(min(1:numel(a), numel(b)))