try this:
dat <- data.frame(x = runif(100),
fac1 = rep(c("a", "b", "c", "d"), each = 25),
fac2 = rep(c("A", "B"), 50))
splits <- c("fac1", "fac2")
split(dat, dat[splits])
I hope it helps.
Best,
Dimitris
On 6/17/2011 2:34 PM, carslaw wrote:
Dear R-users
I seem to be stumped on something simple. I want to split a data frame
by factor levels given in one or more columns e.g. given
dat<- data.frame(x = runif(100),
fac1 = rep(c("a", "b", "c", "d"), each = 25),
fac2 = rep(c("A", "B"), 50))
I know I can split it by fac1, fac2 by:
split(dat, list(dat$fac1, dat$fac2))
which gives a list of length 8 - as desired.
My question is, given a vector of column name(s) to split by, how can I
supply
split with these? I was thinking something like:
splits<- c("fac1", "fac2")
split(dat, list(splits))
But that is clearly wrong....and I can't see the solution
Many thanks
David Carslaw
Science Policy Group
Environmental Research Group
MRC-HPA Centre for Environment and Health
King's College London
Room 4.129 Franklin Wilkins Building
Stamford Street
London SE1 9NH
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--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center
Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
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