strapply in gsubfn can extract matches based on content which seems to be what you want:
library(gsubfn) f <- function(...) sapply(list(...), paste, collapse = ", ") DF <- data.frame(x, Source = strapply(x, "^(\\w+):", c, simplify = f), Mentions = strapply(x, "@(\\w+)", c, simplify = f), HashTags = strapply(x, "#(\\w+)", c, simplify = f)) DF[DF == ""] <- NA On Wed, Mar 31, 2010 at 9:20 AM, Tony B <tony.bre...@googlemail.com> wrote: > Dear all, > > Lets say I have the following: > >> x <- c("Eve: Going to try something new today...", "Adam: Hey @Eve, how are >> you finding R? #rstats", "Eve: @Adam, It's awesome, so much better at >> statistics that #Excel ever was! @Cain & @Able disagree though :(", "Adam: >> @Eve I'm sure they'll sort it out :)", "blahblah") >> x > [1] "Eve: Going to try something new > today..." > [2] "Adam: Hey @Eve, how are you finding R? > #rstats" > [3] "Eve: @Adam, It's awesome, so much better at statistics that > \n#Excel ever was! @Cain & @Able disagree though :(" > [4] "Adam: @Eve I'm sure they'll sort it > out :)" > [5] "blahblah" > > I would like to come up with a data frame which looks like this > (pulling out the usernames and #tags): > >> data.frame(Msg = x, Source = c("Eve", "Adam", "Eve", "Adam", NA), Mentions = >> c(NA, "Eve", "Adam, Cain, Able", "Eve", NA), HashTags = c(NA, "rstats", >> "Excel", NA, NA)) > > The best I can do so far is: > > source <- lapply(x, function (x) { > tmp <- strsplit(x, ":", fixed = TRUE) > if(length(tmp[[1]]) < 2) { > tmp <- c(NA, tmp) > } > return(tmp[[1]][1]) > } ) > source <- unlist(source) > > [1] "Eve" "Adam" "Eve" "Adam" NA > > I can't work out how to extract the usernames starting with '@' or the > #tags. I can identify them using gsub and replace them, but I don't > know how to just extract those terms only, e.g. sort of the opposite > of the following > >> gsub("@([A-Za-z0-9_]+)", "@[...]", x) > [1] "Eve: Going to try something new today..." > [2] "Adam: Hey @[...], how are you finding R? #rstats" > [3] "Eve: @[...], It's awesome, so much better at statistics that > #Excel ever was! @[...] & @[...] disagree though :(" > [4] "Adam: @[...] I'm sure they'll sort it out :)" > [5] "blahblah" > > and > >> gsub("#([A-Za-z0-9_]+)", "#[...]", x) > [1] "Eve: Going to try something new today..." > [2] "Adam: Hey @Eve, how are you finding R? #[...]" > [3] "Eve: @Adam, It's awesome, so much better at statistics that > #[...] ever was! @Cain & @Able disagree though :(" > [4] "Adam: @Eve I'm sure they'll sort it out :)" > [5] "blahblah" > > I hope that makes sense, and thank you kindly in advance for your > time. > Tony Breyal > > ______________________________________________ > 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.