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Ho to repeat a vector?

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M G
M G on 24 Nov 2012
Hi all,
Could anybody plz be a help me what is the build-in function for:
repvec (1:5, 2)
which results in:
ans = 1 1 2 2 3 3 4 4 5 5
Thank you so much for your help :)

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Jordan Lessentier
Jordan Lessentier on 2 May 2017
https://fr.mathworks.com/help/matlab/ref/repelem.html

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Answers (4)

Matt Fig
Matt Fig on 24 Nov 2012
Edited: Matt Fig on 24 Nov 2012
vec = 1:5;
reshape(vec([1 1],:),1,[])
% Or reshape(vec(ones(1,N),:),1,[]) to expand N times
For more complex expansions, give this file a try: EXPAND

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Image Analyst
Image Analyst on 24 Nov 2012
If you have the Image Processing Toolbox, you can do it this way
out = imresize(a, [1 10], 'nearest')
where a is your 1:5 vector, and the 10 is how long you want the output to be.

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Jan
Jan on 25 Nov 2012
+1: While this is not very efficient, it is a creative recycling of the Signal Processing toolbox.

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Azzi Abdelmalek
Azzi Abdelmalek on 24 Nov 2012
Edited: Azzi Abdelmalek on 24 Nov 2012
vec=1:5
out=[vec;vec];
out=out(:)'
If you want to repeat n times
vec=1:5
n=10;
out=repmat(vec,n,1);
out=out(:)';

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Jan
Jan on 25 Nov 2012
While I'd prefer Matt Fig's approach in real programs, here another approach, which might be interesting:
vec = 1:5;
n = 2;
index = zeros(1, length(vec) * n);
index(1:n:end) = 1;
index = cumsum(index);
result = vec(index);

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