On Jan 4, 2013, at 7:30 AM, Sam Steingold wrote:
Hi,
to count vector elements with some property, the standard idiom seems to
be length(which):
--8<---------------cut here---------------start------------->8---
x <- c(1,1,0,0,0)
count.0 <- length(which(x == 0))
--8<---------------cut here---------------end--------------->8---
however, this approach allocates and discards 2 vectors: a logical
vector of length=length(x) and an integer vector in which.
is there a cheaper alternative?
I don't know if it is "cheaper", but the way I "learned to count" was:
sum(x==8, na.rm=TRUE)
--
David Winsemius
Alameda, CA, USA
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