normalize all but the zeros in a vector?

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mark palmer 2023-12-24

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https://ww2.mathworks.cn/matlabcentral/answers/2063782-normalize-all-but-the-zeros-in-a-vector

评论： Walter Roberson 2023-12-24

采纳的回答： Dyuman Joshi

I have a vector that contains 0s, something like this [44 0 23 19 0 0 30]

and I want to normalize the non-0 elements to 1-10, for instance, but the 0s keep messing it up.

Is there a way (hopefully without using loops) to normalize while not affecting the 0s? In other words, take the values from 19-44 and convert them to stretch over 1-10.

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采纳的回答

Dyuman Joshi 2023-12-24

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https://ww2.mathworks.cn/matlabcentral/answers/2063782-normalize-all-but-the-zeros-in-a-vector#answer_1377067

编辑：Dyuman Joshi 2023-12-24

在 MATLAB Online 中打开

%Input
in = [44 0 23 19 0 0 30];
%Lazy preallocation, assuming all values are finite and not NaNs
out = 0*in;
%Indexing for non-zeros values
idx = in~=0;
%Output
out(idx) = rescale(in(idx), 1, 10)
out = 1×7
   10.0000         0    2.4400    1.0000         0         0    4.9600

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Dyuman Joshi 2023-12-24

"But as soon as I say that, it will happen."

Haha, yes.

Mine used to be that too, but I am not sure how it changed into multiplying with 0. I think I'll go back to using zeros() soon, specially noting the difference in speed.

However, keeping performance in mind, maybe I should revisit this thread - https://in.mathworks.com/matlabcentral/answers/51411-initialize-a-mxn-matrix-with-the-same-number#answer_453549