Is this what you want: > "var3" %in% names(ipf) [1] FALSE > "var1" %in% names(ipf) [1] TRUE >
On Tue, Jul 29, 2008 at 6:20 PM, <[EMAIL PROTECTED]> wrote: > > Hello R mailing list > > Is there a better way than this to see if an element exists *within* a > list object : > > #generate "file.txt" using current routine > cat("var1=33\nvar2=TRUE",file="file.txt") > > #load file to a list called "ipf" > f <- function(.file){source(.file,local=TRUE);as.list(environment())} > ipf<- f("file.txt") > > print(ipf) > > > #this is the bit I need help with... > res <- match("var1",names(ipf)) # returns result > 0 if "var" exists > within ipf ie. TRUE > print(res) > res <- match("var3",names(ipf)) #returns NA as "var3" is not in ipf ie. > FALSE > print(res) > > I have tried the exists function but cannot get it to apply to items of > a list (though can get it to see if the list exists as an object...) > > Thanks > Paul. > > Paul Rustomji > Rivers and Estuaries > CSIRO Land and Water > GPO Box 1666 > Canberra ACT 2601 > > ph +61 2 6246 5810 > mobile 0406 375 739 > > ______________________________________________ > R-help@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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem you are trying to solve? ______________________________________________ R-help@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.