[R] matching period with perl regular expression

[(Ted Harding)]

On 13-May-09 23:47:41, Henrique Dallazuanna wrote:
> Try this:
> 
> gsub("^(\\w*).*$", "\\1", x)

Even simpler:
  x
# [1] "wa.w"
  gsub("\\..*","",x,perl=TRUE)
# [1] "wa"
  x<-"abcde.fghij.klmno"
  gsub("\\..*","",x,perl=TRUE)
# [1] "abcde"

(and it doesn't matter whether 'perl' is TRUE or FALSE)

Ted.

> On Wed, May 13, 2009 at 8:41 PM, Stephen J. Barr
> <stephenjbarr at gmail.com>wrote:
> 
>> Hello,
>>
>> I have several strings where I am trying to eliminate the period and
>> everything after the period, using a regular expression. However, I am
>> having trouble getting this to work.
>>
>> > x = "wa.w"
>> > gsub(x, "\..*", "", perl=TRUE)
>> [1] ""
>> Warning messages:
>> 1: '\.' is an unrecognized escape in a character string
>> 2: unrecognized escape removed from "\..*"
>>
>> In perl, you can match a single period with \.
>> Is this not so even with perl=TRUE. I would like for x to be equal to
>> > x = "wa"
>>
>> What am I missing here?
>> -stephen
>> ==========================================
>> Stephen J. Barr
>> University of Washington
>> WEB: www.econsteve.com
>>
>> ______________________________________________
>> R-help at 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.
>>
> 
> 
> 
> -- 
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O
> 
>       [[alternative HTML version deleted]]
> 

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Date: 14-May-09                                       Time: 00:58:07
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