[R] perhaps regular expression bug with | sign ??

[Henrique Dallazuanna]

Try this:

sub(x='>|t|',pattern = '\\|t',replacement='zz')

On Fri, Apr 9, 2010 at 5:35 PM, David.Epstein
<David.Epstein at warwick.ac.uk> wrote:
>
> Here is my interaction with R:
>> sub(x='>|t|',pattern = '|t',replacement='zz')
> [1] "zz>|t|"
>
> So I say to myself "Clearly the | signs need to be escaped, so let's try
> this"
>> sub(x='>|t|',pattern = '\|t',replacement='zz')
> [1] "zz>|t|"
> Warning messages:
> 1: '\|' is an unrecognized escape in a character string
> 2: unrecognized escape removed from "\|t"
> How can \| be an unrecognized escape? This flatly contradicts help('regex'),
> or am I misunderstanding the help?
>
> The first pattern above works if one uses extended=F.
>
> What do R experts think?
>
> David
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-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O