[R] Matching a period in grep...

Alec.Zwart at csiro.au Alec.Zwart at csiro.au
Wed Aug 6 03:55:52 CEST 2008


Hi folks, 

Can anyone enlighten me as to why I get the following when I search for
".csv" at the end of a string?

> grep("\.csv$","Blah.csv",value=TRUE)

[1] "Blah.csv"
Warning messages:
1: '\.' is an unrecognized escape in a character string 
2: unrecognized escape removed from "[\.]csv$"


R reference for regular expressions says

"Any metacharacter with special meaning may be quoted by preceding it
 with a backslash. [...] The metacharacters in EREs are . \ | ( ) [ { ^
$ * + ?" 

Am I missing something here?  If "\." is not the right way to match a
period, can anyone tell me what is?  I can't find anything on this in R
reference...

I'm using R 2.6 on Windows XP

Thanks, 

Alec Zwart
CMIS CSIRO
alec.zwart at csiro.au 



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