vectorizing problem
try this:
GPL <- data.frame(x = c(2315100, 2315106),
y = c("NR_024005,NR_024004,AK093685", "DQ786314"))
sp <- strsplit(as.character(GPL$y), ",")
ni <- sapply(sp, length)
data.frame(x = rep(GPL$x, ni), y = unlist(sp))
I hope it helps.
Best,
Dimitris
On 10/4/2010 7:54 PM, Dylan Miracle wrote:
Hello,
I have a two column dataframe that
has entries that look like this:
2315100 NR_024005,NR_024004,AK093685
2315106 DQ786314
and I want to change this to look like this:
2315100 NR_024005
2315100 NR_024004
2315100 AK093685
2315106 DQ786314
I can do this with the following "for" loop but the dataframe (GPL)
has ~140,000 rows and this takes about 15 minutes:
extGPL<- matrix(nrow=0,ncol=2)
for (i in 1:length(GPL[,2])){
aa<- unlist(strsplit(as.character(GPL[i,2]),"\\,"))
bb<- rep(as.numeric(as.character(GPL[i,1])), length(aa))
cc<- matrix(c(bb,aa),ncol = 2)
extGPL<- rbind(extGPL,cc)
}
Is there a way to vectorize this?
Thanks,
Dylan Miracle
University of Minnesota
GCD Department
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Dimitris Rizopoulos Assistant Professor Department of Biostatistics Erasmus University Medical Center Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands Tel: +31/(0)10/7043478 Fax: +31/(0)10/7043014 Web: http://www.erasmusmc.nl/biostatistiek/