create vector of repeating elements (sort of)

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Leor Greenberger
Leor Greenberger 2011-9-20
评论： HC Song 2017-6-1
How can I easily create a vector such that:
w = 3
n = 8
v = (1 w times) (2 w times) (3 w times) ... (n w times)
so i would have:
v = [1 1 1 2 2 2 3 3 3 4 4 4 .... 8 8 8]

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采纳的回答

the cyclist
the cyclist 2011-9-20
Here is one way:
w = 3;
n = 8;
v = repmat(1:n,[w 1])
v = v(:)'

更多回答（4 个）

Oleg Komarov
Oleg Komarov 2011-9-20
For variable w use rude from the fex:
rude(len,val)
Richard Tyson
Richard Tyson 2013-8-15
If you need it to be fast you should avoid using repmat. Stick to C functions which don't need to parse input arguments and do one specific task:
n = 8;
w = 3;
v = ceil( [1:(w*n)]./w )
If anyone has a faster way please post. I do this kind of operation a lot.
  2 个评论
the cyclist
the cyclist 2013-8-15
This thread is nearly two years old. You might want to post this as a new question.
Artur Palha
Artur Palha 2014-9-25
n = 8; w = 3; v = rectpulse(1:n)
This is the fastest option I know of.

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Lucas García
Lucas García 2011-9-20
One of many ways:
>> w = 3; n = 8;
>> v = repmat(1:n,w,1);
>> v = v(1:end)
Wayne King
Wayne King 2011-9-20
One way:
w = 3;
x = 1:8;
x = arrayfun(@(x) repmat(x,1,w),x,'UniformOutput',false);
x = cell2mat(x);
Wayne
  1 个评论
Jan
Jan 2011-9-20
ARRAYFUN and CELL2MAT needs a lot of time. Using REPMAT directly is much faster.

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