[R] Regular Expressions in grep

[Bert Gunter]

grep() returns the matches. You want regexpr() and regmatches()

-- Bert

On Tue, Aug 21, 2012 at 12:24 PM, Dr. Holger van Lishaut
<H.v.Lishaut at gmx.de> wrote:
> Dear r-help members,
>
> I have a number in the form of a string, say:
>
> a<-"-01020.909200"
>
> I'd like to extract "1020." as well as ".9092"
>
> Front<-grep(pattern="[1-9]+[0-9]*\\.", value=TRUE, x=a, fixed=FALSE)
> End<-grep(pattern="\\.[0-9]*[1-9]+", value=TRUE, x=a, fixed=FALSE)
>
> However, both strings give "-01020.909200", exactly a.
> Could you please point me to what is wrong?
>
> Thanks and best regards
> H. van Lishaut
>
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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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