== is also vectorised, and you're better off with TRUE and FALSE rather than 1 and 0, so I'd recommend:
colordata$response <- colordata$color == 'blue' Hadley On Thu, Apr 7, 2016 at 6:52 AM, David Barron <dnbar...@gmail.com> wrote: > ifelse is vectorised, so just use that without the loop. > > colordata$response <- ifelse(colordata$color == 'blue', 1, 0) > > David > > On 7 April 2016 at 12:41, Michael Artz <michaelea...@gmail.com> wrote: > >> Hi I'm not sure how to ask this, but its a very easy question to answer for >> an R person. >> >> What is an easy way to check for a column value and then assigne a new >> column a value based on that old column value? >> >> For example, Im doing >> colordata <- data.frame(id = c(1,2,3,4,5), color = c("blue", "red", >> "green", "blue", "orange")) >> for (i in 1:nrow(colordata)){ >> colordata$response[i] <- ifelse(colordata[i,"color"] == "blue", 1, 0) >> } >> >> which works, but I don't want to use the for loop I want to "vecotrize" >> this. How would this be implemented? >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. >> > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. -- http://hadley.nz ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.