How can I use "IF" statement to prevent adding same element to an array?
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Hello,
So I have a matrix A
A = [ 1 2 3;
2 3 4;
4 5 6]
I create another matrix B where B =[] and the element in B will be added from A. Matrix B becomes
B = [ 1 2;
2 3;
3 1;
2 3;
3 4;
4 2]
The forloop technically go through each row of A to pick the elements for each row of B. B is nx2 matrix. As we can see, "2 3" is repeated. I want to make an If statement that prevent adding existing row in B.
Please help, thank you so much.
采纳的回答
the cyclist
2019-11-15
编辑：the cyclist
2019-11-15
Would it be acceptable to just remove duplicated rows after-the-fact? If so, you could do
B = unique(B,'rows');
It seems likely that this would be more efficient than checking each row against all prior rows, while B is being constructed.
5 个评论
kiet tran
2019-11-15
the cyclist
2019-11-15
Would the following be acceptable?
B = unique(sort(B,2),'row');
This would reduce
[1 2;
2 1]
to just
[1 2]
which seems to be what you want. However, it would also change just
[2 1]
to
[1 2]
even though [1 2] was never present in the first place. Is that OK?
kiet tran
2019-11-15
the cyclist
2019-11-15
I don't know what you mean by "somewhat the same to the existing ones". So, let's be specific.
sort will take each row, and put it in ascending numerical order. Therefore the row [2 1] and the row [1 2] will both become [1 2]. That way, unique keeps only one of those rows.
kiet tran
2019-11-18
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