Hmm.
I have R11 just downloaded fresh.
I'll reload a new session..and revert. I will note that I've had trouble
with \\d
which is why I was using [0-9]
MAC here.
On Wed, May 5, 2010 at 3:00 PM, Gabor Grothendieck
<ggrothendi...@gmail.com>wrote:
> That's not what I get:
>
> >
> test<-"</tr><tr><th>88958</th><th>Abcdsef</th><th>67.8S</th><th>68.9\nW</th><th>26m</th>"
> > sub(".*(\\d{5}).*", "\\1", test)
> [1] "88958"
> > R.version.string
> [1] "R version 2.10.1 (2009-12-14)"
>
> I also got the above in R 2.11.0 patched as well.
>
>
> On Wed, May 5, 2010 at 5:55 PM, steven mosher <mosherste...@gmail.com>
> wrote:
> > test
> > [1]
> >
> "</tr><tr><th>88958</th><th>Abcdsef</th><th>67.8S</th><th>68.9\nW</th><th>26m</th>"
> >> sub(".*(\\d{5}).*", "\\1", test)
> > [1] "</th>"
> >> sub(".*([0-9]{5}).*","\\1",test)
> > [1] "88958"
> >>
> >
> > I think the "</" in the source throws something off.
> > as the group capture appears to not be working, except the bracket
> version
> > it did.
> >
> > On Wed, May 5, 2010 at 2:35 PM, Gabor Grothendieck <
> ggrothendi...@gmail.com>
> > wrote:
> >>
> >> Here are two ways to extract 5 digits.
> >>
> >> In the first one \\1 refers to the portion matched between the
> >> parentheses in the regular expression.
> >>
> >> In the second one strapply is like apply where the object to be worked
> >> on is the first argument (array for apply, string for strapply) the
> >> second modifies it (which dimension for apply, regular expression for
> >> strapply) and the last is a function which acts on each value
> >> (typically each row or column for apply and each match for strapply).
> >> In this case we use c as our function to just return all the results.
> >> They are returned in a list with one component per string but here
> >> test is just a single string so we get a list one long and we ask for
> >> the contents of the first component using [[1]].
> >>
> >> # 1 - sub
> >> sub(".*(\\d{5}).*", "\\1", test)
> >>
> >> # 2 - strapply - see http://gsubfn.googlecode.com
> >> library(gsubfn)
> >> strapply(test, "\\d{5}", c)[[1]]
> >>
> >>
> >>
> >> On Wed, May 5, 2010 at 5:13 PM, steven mosher <mosherste...@gmail.com>
> >> wrote:
> >> > Given a text like
> >> >
> >> > I want to be able to extract a matched regular expression from a piece
> >> > of
> >> > text.
> >> >
> >> > this apparently works, but is pretty ugly
> >> > # some html
> >> >
> >> >
> test<-"</tr><tr><th>88958</th><th>Abcdsef</th><th>67.8S</th><th>68.9\nW</th><th>26m</th>"
> >> > # a pattern to extract 5 digits
> >> >> pattern<-"[0-9]{5}"
> >> > # regexpr returns a start point[1] and an attribute "match.length"
> >> > attr(,"match.length)
> >> > # get the substring from the start point to the stop point.. where
> stop
> >> > =
> >> > start +length-1
> >> >>
> >> >
> >> >
> answer<-substr(test,regexpr(pattern,test)[1],regexpr(pattern,test)[1]+attr(regexpr(pattern,test),"match.length")-1)
> >> >> answer
> >> > [1] "88958"
> >> >
> >> > I tried using sub(pattern, replacement, x ) with a regexp that
> captured
> >> > the
> >> > group. I'd found an example of this in the mails
> >> > but it didnt seem to work..
> >
> >
>
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list
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.
