On 17/09/2015 5:11 PM, Dimitri Liakhovitski wrote: > (x <- c("q10_1", "q10_2", "q10_11", "q12_1", "q12_2", "q13_1", "q13_11")) > > # Which strings start with "q10" or "q12? - WORKS > x[grep("^q10|q12", x)] > > # Which strings end with "1"? - WORKS > x[grep("1$", x)] > > # Which strings end with "_1"? - WORKS > x[grep("\\_1$", x)] > > # Which strings start with "q10" AND contain a "1"? - WORKS > x[grep("^q10.+1", x)] > > # Which strings start with "q10" AND end with a "_1"? - DOES NOT WORK > x[grep("^q10.+\\_1$", x)]
Your verbal description doesn't match your regexp, and you didn't show us your output, so how can we tell whether this is you not understanding regular expressions, or an actual problem? When I try this example, I get character(0) which is the correct outcome, given the input string. Duncan Murdoch > > # Which strings start with "q10" or "q12 AND end with "_1"? - WORKS > INCORRECTLY > x[grep("^q10|q12.+\\_1$", x)] > > Thank you! > Dimitri Liakhovitski > > ______________________________________________ > 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. > ______________________________________________ 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.