How to generate k unique random numbers from 1 to n in matlab 2009

Hi, I knew randperm(n,k) works but this is after 2011. Can some one tell me if there is any efficient way to do it in matlab 2009.

Thanks

Answer 1

[Azzi Abdelmalek]

[idx,idx]=sort(rand(1,n));
out=idx(1:k)

[Jan]

The result is biased, because Matlab's sort is stable. The effects are very tiny and they appear in Matlab's randperm function with 1 input argument also.

Answer 2

[Zhang lu]

a=randperm(n); b=a(1:k)

Answer 3

[Jan]

Not biased and faster than sorting a RAND vector: http://www.mathworks.com/matlabcentral/fileexchange/27076-shuffle