[R] Question to regular expressions

Antje niederlein-rstat at yahoo.de
Tue Dec 2 16:48:04 CET 2008


Hi Gabor,

it works! Thank you very much! But I still don't understand the difference 
between [0-9] and [:digit:]...

Ciao,
Antje


Gabor Grothendieck schrieb:
> Try this:
> 
>> folders <- c("folder1", "f2", "F234562", "12345678", "234567", "912345", "333")
>> grep("^[0-9]{6}$", folders, value = TRUE)
> [1] "234567" "912345"
> 
> 
> On Tue, Dec 2, 2008 at 10:32 AM, Antje <niederlein-rstat at yahoo.de> wrote:
>> Hi there,
>>
>> I know, this question is not directly an R-help question but probably
>> someone can give me a hint how to deal with the following problem.
>>
>> I have a vector with file/folder names and want to filter for all entries
>> which  have 6 numbers in a row and nothing else.
>>
>> folders <- c("folder1", "f2", "F234562", "12345678", "234567", "912345",
>> "333")
>>
>> I'd like to get only "234567" and "912345".
>> Can anybody help me creating a regex for this???
>>
>> For example this regex:
>>
>> regexpr("[^:digit:$]{6}", folders)
>>
>> would match "F234562", "12345678", "234567", "912345"
>>
>>
>> Antje
>>
>> ______________________________________________
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>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>



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