# Create a 2d matrix with two nested cycle

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SYML2nd on 1 Sep 2020
Answered: Rik on 1 Sep 2020
Hi all,
I am trying to create a 2d matrix with two nested cycle. My code is really complex, so I have written a very simple version of the problem. The scope of this simplified code was to obtain
[1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4]
So I have written a code like this
A=[]
B=[]
for x=1:1:4
for y=1:1:4
B=[B;y]
end
A=[A,B]
end
The problem seems to me that the nested cycle continue to append the value of y also once the cycle is ended. So when I do A=[A,B], I have the error that the array concatenated are not consistent.
I hope you can help me.
PS I know that this example of matrix can be obtained very easily, I want to obtain it using the nested cycles.

Rik on 1 Sep 2020
Dynamically growing arrays is a bad idea. You should probably provide more details about your actual goal, because this problem definition doesn't make sense.
A=[];
for x=1:1:4
B=[];%reset B every loop of A
for y=1:1:4
B=[B;y];
end
A=[A,B];
end
A