How can I remove for loop in the following code that change the entries of a given vector?

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Hassan 2018-1-7

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https://ww2.mathworks.cn/matlabcentral/answers/375985-how-can-i-remove-for-loop-in-the-following-code-that-change-the-entries-of-a-given-vector

编辑： Matt J 2018-1-7

采纳的回答： Star Strider

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Hello, I am trying to vectorize the following simple code

if true
A=[-1;3;0;-4];
B=zeros(size(A));
for i=1:4
  if A(i)<0
      B(i)=-(A(i));
  elseif A(i)==0
      B(i)=1;
  else
      B(i)=A(i);
  end
  B=B(:);
end  
end
Please, how do I write the above code in such a way that there is no for loop, and still it works?

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Matt J 2018-1-7

Please indent your code, but not your text. It makes your post hard to read, otherwise.

Hassan 2018-1-7

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采纳的回答

Star Strider 2018-1-7

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https://ww2.mathworks.cn/matlabcentral/answers/375985-how-can-i-remove-for-loop-in-the-following-code-that-change-the-entries-of-a-given-vector#answer_299024

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Try this:

A=[-1;3;-2;-4];
B = A;
B(A<0) = -A(A<0)

Note that it is necessary to determine the number of zeros, so the vector of non-zero values that replaces them is the same size. I used random single-digit positive integers, although any vector with the same number of non-zero values as there are zero values in the vector will work.

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