问题
Is there a way to extend a vector by making it repeat itself?
>v = [1 2];
>v10 = v x 5; %x represents some function. Something like "1 2" x 5 in perl
Then v10 would be:
>v10
1 2 1 2 1 2 1 2 1 2
This should work for the general case, not just for [1 2]
回答1:
The function you're looking for is repmat().
v10 = repmat(v, 1, 5)
回答2:
Obviously repmat is the way to go if you know in which direction you want to expand the vector.
However, if you want a general solution that always repeats the vector in the longest direction, this combination of repmat and indexing should do the trick:
v10=v(repmat(1:length(v),1,5))
来源：https://stackoverflow.com/questions/2459851/octave-matlab-extend-a-vector-making-it-repeat-itself