[R] random section of samples based on group membership
Wade Wall
wade.wall at gmail.com
Mon Jul 24 17:18:10 CEST 2006
Hi all,
I have a matrix of 474 rows (samples) with 565 columns (variables).
each of the 474 samples belong to one of 120 groups, with the
groupings as a column in the above matrix. For example, the group
column would be:
1
1
1
2
2
2
.
.
.
120
120
I want to randomly select one from each group. Not all the groups
have the same number of samples, some have 4, some 3 etc. Is there a
function to do this, or would I need to write a looping statement to
look at each successive group?
I basically want to combine the randomly selected samples from the 120
groups into a new matrix in order to perform a cluster analysis.
Thanks,
Wade
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