On 17/09/2015 5:46 PM, Dimitri Liakhovitski wrote: > Duncan, > Of course my verbal descriptions and my code don't match my regexp - > otherwise I wouldn't be asking the question, would I? > Please assume my verbal descriptions are correctly describing what I want.
Sorry, I interpreted "works" and "does not work" to be saying that R's regexp matching was working or not. I think you've got your answers from others now... Duncan Murdoch > Thank you! > > On Thu, Sep 17, 2015 at 5:42 PM, Duncan Murdoch > <murdoch.dun...@gmail.com> wrote: >> 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.