How can I do the average between many vector columns?

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Adrian 2014-4-16

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/126014-how-can-i-do-the-average-between-many-vector-columns

评论： Umesh Gautam 2023-11-7

I have 120 1x500 vector columns, so I can't do it manually. For example, I have the following vector columns, each 1x500 in size:

a1, a2, ......, an, where n=120

I want to do:

(a1 + a2 + ... + an)/n

Thank you very much!

Adrian

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Answer 1

José-Luis 2014-4-16

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https://ww2.mathworks.cn/matlabcentral/answers/126014-how-can-i-do-the-average-between-many-vector-columns#answer_133581

编辑：José-Luis 2014-4-16

在 MATLAB Online 中打开

%Creating vectors:
for ii = 1:50
    str = ['a' num2str(ii)];
    assignin('base',str,rand(100,1));
end
%Preallocating:
your_mat = ones(100,50);
%Putting everything together, this is the part you want if you already have the vectors
for ii = 1:50
    str = ['a' num2str(ii)];
    your_mat(:,ii) = evalin('base',str);
end
your_val = mean(your_mat(:));

Please accept an answer if it helps you.

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Adrian 2014-4-17

Thank you for your answer. But the thing is that it gives me just a number, because that's what 'mean' function does, it gives a single number. When I average my 120 500x1 column vectors, namely (a1 + a2 + ... + an)/n, where n=120, it should give me a 500x1 vector column, not a single number.

If you could help further, that would be great! Thanks

lvn 2014-4-17

在 MATLAB Online 中打开

Replace the last line of Jose-Luis code with

your_val = mean(your_mat);

Then you will have what you want. However, much better would be to initially read in/or store your data in a matrix, rather than in separate vectors, then you can simply use what Azzi wrote.

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