[R] Randomly splitting a data frame in half
Christopher David Desjardins
cddesjardins at gmail.com
Thu Mar 19 19:20:57 CET 2009
Thanks that makes perfect sense!
On 3/19/09 1:17 PM, Dimitris Rizopoulos wrote:
> well, you need to keep track of the rows you sampled, e.g.,
> dat <- data.frame(x = rnorm(20), y = rnorm(20), w = rnorm(20))
> ii <- seq_len(nrow(dat))
> ind1 <- sample(ii, 10)
> ind2 <- ii[!ii %in% ind1]
> dat[ind1, ]
> dat[ind2, ]
> I hope it helps.
> Christopher David Desjardins wrote:
>> I have a data frame in long format and I would like to randomly
>> divide this data frame in half. The data frame consists of 39622 rows
>> and I initially tried ...
>> randomsample1 <- data[sample(nrow(data),19811), ]
>> Where allows me to randomly select half of the rows and assign them
>> to randomsample1 but then I couldn't figure out how to select those
>> rows that were not selected and assign them to randomsample2.
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>> and provide commented, minimal, self-contained, reproducible code.
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