taking samples from a vector

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Paul Rogers 2020-9-21

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/597460-taking-samples-from-a-vector

评论： Star Strider 2020-9-21

采纳的回答： Star Strider

psi.mat

在 MATLAB Online 中打开

I have the vector psi. It has too many items and I cannot copy and paste the values in a txt file to plot a graph in Latex.

Would be great to have a small code to take a sample like every 5 or 10 items to reduce the size and create a new file psi_short.

It won't lose the shape since its dicretization is very high.

I wrote this but it doesn change anithyng:

for i=1:length(psi)
        psi_short(i) =psi(i);
        i=i+5;
   end

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Star Strider 2020-9-21

Use my code.

It is not possible to change the index in a for loop. The for function simply ignores the changes (although you can use changed values for it in calculations).

Even if it worked, the explicit loop is much less efficient than the indexing approach my code uses.

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采纳的回答

Star Strider 2020-9-21

2
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/597460-taking-samples-from-a-vector#answer_498115

在 MATLAB Online 中打开

Try these:

D = load('psi.mat');
psi = D.psi;                                    % (10962 x 1)
Every5 = psi(1:5:end);                          % (2193 x 1)
Every10 = psi(1:10:end);                        % (1097 x 1)