Flip a vector using for

Question

The Canary Cry 2018-3-15

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https://ww2.mathworks.cn/matlabcentral/answers/388587-flip-a-vector-using-for

编辑： Andrei Bobrov 2018-3-15

I'm a MATLAB beginner in need of some help. I need to flip a vector so that it goes in reverse. Basically, [1 2 3] becomes [3 2 1]; Here's what I've got:

 vector=[1:12]
 A=0;
 j=12;
 for i=1:12
    A=vector(i);
    vector(i)=vector(j);
    vector(j)=A;
    j=j-1;
 end
 vector

I'm not really sure why it's not working since this seems like the logical way to do it.

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Answer 1

Andrei Bobrov 2018-3-15

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https://ww2.mathworks.cn/matlabcentral/answers/388587-flip-a-vector-using-for#answer_310227

编辑：Andrei Bobrov 2018-3-15

在 MATLAB Online 中打开

out = flip(yourvector);

with loop (no use)

out = zeros(size(yourvector));
k = 1;
for ii = numel(yourvector):-1:1
    out(k) = yourvector(ii);
    k = k + 1;
end

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The Canary Cry 2018-3-15

Yes, I know there a functions to do it for me but I need to do it using for.

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Answer 2

James Tursa 2018-3-15

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/388587-flip-a-vector-using-for#answer_310228

编辑：James Tursa 2018-3-15

在 MATLAB Online 中打开

Because you are exchanging elements, you wind up flipping the vector twice, which gets it back to the original state. Instead, just run your for-loop through 1/2 of the vector so that the elements are only flipped once. E.g.,

for i=1:floor(numel(vector)/2)