3 messages · Stephen Eglen, Eik Vettorazzi, PIKAL Petr
Anyone got a neat way to chop a vector up into smaller subvectors?
This is what I have now, which seems inelegant:
chop <- function(v, counts) {
stopifnot(sum(counts)==length(v))
end <- cumsum(counts)
beg <- c(1, 1+end[-length(end)])
begend <- cbind(beg, end)
apply(begend, 1, function(x) v[x[1]:x[2]])
}
chop(9:1, c(3,2,4))
[[1]] [1] 9 8 7 [[2]] [1] 6 5 [[3]] [1] 4 3 2 1
Hi Stephen,
how about this:
chop<-function(x,counts){
stopifnot(sum(counts)==length(x))
split(9:1,unlist(mapply(rep,seq_along(counts),counts)))
}
chop(9:1,c(3,2,4))
cheers
Am 02.08.2012 12:29, schrieb Stephen Eglen:
Anyone got a neat way to chop a vector up into smaller subvectors?
This is what I have now, which seems inelegant:
chop <- function(v, counts) {
stopifnot(sum(counts)==length(v))
end <- cumsum(counts)
beg <- c(1, 1+end[-length(end)])
begend <- cbind(beg, end)
apply(begend, 1, function(x) v[x[1]:x[2]])
}
chop(9:1, c(3,2,4))
[[1]] [1] 9 8 7 [[2]] [1] 6 5 [[3]] [1] 4 3 2 1
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Eik Vettorazzi Department of Medical Biometry and Epidemiology University Medical Center Hamburg-Eppendorf Martinistr. 52 20246 Hamburg T ++49/40/7410-58243 F ++49/40/7410-57790 -- Pflichtangaben gem?? Gesetz ?ber elektronische Handelsregister und Genossenschaftsregister sowie das Unternehmensregister (EHUG): Universit?tsklinikum Hamburg-Eppendorf; K?rperschaft des ?ffentlichen Rechts; Gerichtsstand: Hamburg Vorstandsmitglieder: Prof. Dr. Guido Sauter (Vertreter des Vorsitzenden), Dr. Alexander Kirstein, Joachim Pr?l?, Prof. Dr. Dr. Uwe Koch-Gromus
Hi one of possible options f<- function(x, parts) split(x,rep(1:length(parts),parts)) f(9:1, c(3,2,4)) $`1` [1] 9 8 7 $`2` [1] 6 5 $`3` [1] 4 3 2 1 You can also check if your parts vector agrees with x vector, if you want. Regards Petr
Anyone got a neat way to chop a vector up into smaller subvectors?
This is what I have now, which seems inelegant:
chop <- function(v, counts) {
stopifnot(sum(counts)==length(v))
end <- cumsum(counts)
beg <- c(1, 1+end[-length(end)])
begend <- cbind(beg, end)
apply(begend, 1, function(x) v[x[1]:x[2]])
}
chop(9:1, c(3,2,4))
[[1]] [1] 9 8 7 [[2]] [1] 6 5 [[3]] [1] 4 3 2 1
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.