Sampling small data frame from a big dataframe

Question

I am trying to sample a data frame from a given data frame such that there are enough samples from each of the levels of a variable. This can be achieved by separating the d

Answer 1

It would seem that if you want to sample a category that has less than 20 rows, you'd need replace=TRUE...

This might do the trick:

ddply(data1,'a',function(x) x[sample.int(NROW(x),20,replace=TRUE),])