Choose randomly rows in a matrix

2013 6 12
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Hi I have a matrix with 2 columns, the first is for 'ID', the second is for 'age'. I want to randomly pick 'n'(e.g. 2) IDs of the matrix and return the IDs and the age of the same row.
Thanks

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Sean de Wolski
Sean de Wolski 2013-6-12

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doc randperm
Then use the output of this as an index into your matrix.
x = magic(10);
idx = randperm(10,2)
x(idx,:)

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Vanessa
Vanessa 2013-6-13
when I write idx=randperm(10,2)
??? Error using ==> randperm Too many input arguments.
Walter Roberson
Walter Roberson 2013-6-13
You are using an old version of MATLAB that does not support that syntax for randperm. Instead use
idx = randperm(size(x,1));
x(idx(1:2),:)
Vanessa
Vanessa 2013-6-13
it works :) thanks Walter

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Vanessa
Vanessa
2013-6-12

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