[R] grep

[Andrew Simmons]

?regex is a nice starting point, it's got plenty of details on meta
characters and characters classes, if you need more advanced stuff you'll
probably have to look at the perl regex documentation, I believe it's
linked in ?regex.

I might try something like

grep("^[xz]\\.")

or

grep("^[xz][.]")

or if you'd consider a different function,

startsWith(jj, "x.") | startsWith(jj, "z.")

On Sun, Jul 10, 2022, 21:49 Steven T. Yen <styen using ntu.edu.tw> wrote:

> Thanks Jeff. It works. If there is a good reference I should read
> (besides ? grep) I's be glad to have it.
>
> On 7/11/2022 9:30 AM, Jeff Newmiller wrote:
> > grep( "^(z|x)\\.", jj, value = TRUE )
> >
> > or
> >
> > grep( r"(^(z|x)\.)", jj, value = TRUE )
> >
> >
> > On July 10, 2022 6:08:45 PM PDT, "Steven T. Yen" <styen using ntu.edu.tw>
> wrote:
> >> Dear, Below, jj contains character strings starting with “z.” and “x.”.
> I want to grep all that contain either “z.” or “x.”. I had to grep “z.” and
> “x.” separately and then tack the result together. Is there a convenient
> grep option that would grep strings with either “z.” or “x.”. Thank you!
> >>
> >>> jj<-names(v$est); jj
> >>   [1] "z.one"     "z.liberal" "z.conserv" "z.dem"     "z.rep"
> "z.realinc"
> >>   [7] "x.one"     "x.liberal" "x.conserv" "x.dem"     "x.rep"
> "x.realinc"
> >> [13] "mu1_1"     "mu2_1"     "rho"
> >>> j1<-grep("z.",jj,value=TRUE); j1
> >> [1] "z.one"     "z.liberal" "z.conserv" "z.dem"     "z.rep" "z.realinc"
> >>> j2<-grep("x.",jj,value=TRUE); j2
> >> [1] "x.one"     "x.liberal" "x.conserv" "x.dem"     "x.rep" "x.realinc"
> >>> j<-c(j1,j2); j
> >>   [1] "z.one"     "z.liberal" "z.conserv" "z.dem"     "z.rep"
> "z.realinc"
> >>   [7] "x.one"     "x.liberal" "x.conserv" "x.dem"     "x.rep"
> "x.realinc"
> >>
> >> ______________________________________________
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> >> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> >> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help using 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.
>

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