R help - Jul 2022 - grep

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 at
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"
>>
>> ______________________________________________
>> R-help at 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.

?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 at 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
at 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"
> >>
> >> ______________________________________________
> >> R-help at 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 at 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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