Perfect. Thank you. -Mitch
-----Original Message----- From: Phil Spector [mailto:spec...@stat.berkeley.edu] Sent: Friday, April 08, 2011 8:03 PM To: Downey, Patrick Cc: r-help@r-project.org Subject: Re: [R] Finding elements in a character vector match(list.a,list.b) - Phil Spector Statistical Computing Facility Department of Statistics UC Berkeley spec...@stat.berkeley.edu On Fri, 8 Apr 2011, Downey, Patrick wrote: > Hello, > > I have two character vectors: list.a and list.b. Every element of > list.a appears somewhere in list.b. Not all elements of list.b are in > list.a, and some elements of list.b appear multiple times in list.a. I > want to create a new vector (index) of the same length as list.a where > the nth element of index is the location in list.b of the nth element of list.a. > > This code will work, but I have heard over and over again that using > loops is inefficient in R and that there are (almost always) better > ways to do things. > > for(i in 1:length(list.a)){ > index[i] <- seq(1,length(list.b))[list.b==list.a[i]] > } > > Thank you, > Mitch > > ______________________________________________ > 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. > ______________________________________________ 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.
