And unless I'm mistaken, escaping the underscore is superfluous (I'd be curious
to know if it's a function of locale).
x[grep("_", x)]
x[grep("^q10.*_1$", x)]
both work.
steve
Stephen C. Upton
SEED (Simulation Experiments & Efficient Designs) Center
Operations Research Department
Naval Postgraduate School
SEED Center web site: http://harvest.nps.edu
-----Original Message-----
From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Berend Hasselman
Sent: Friday, September 18, 2015 1:30 AM
To: Dimitri Liakhovitski
Cc: r-help
Subject: Re: [R] Hep with regex! - combination of ^, |, \\, _ and $
> On 17 Sep 2015, at 23:11, Dimitri Liakhovitski
> <dimitri.liakhovit...@gmail.com> 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)]
>
For these last to this should “work”
> # Which strings start with "q10" AND end with a "_1"? - DOES NOT WORK
> x[grep("^q10.+\\_1$", x)]
>
x[grep("^q10.*\\_1$", x)]
> # Which strings start with "q10" or "q12 AND end with "_1"? - WORKS
> INCORRECTLY x[grep("^q10|q12.+\\_1$", x)]
>
x[grep("^q10|q12.*\\_1$", x)]
It’s the .+ that’s the problem.
Berend
> Thank you!
> Dimitri Liakhovitski
>
> ______________________________________________
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______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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