[R] regular expression help

C Lin baccts at hotmail.com
Fri Jun 27 03:11:46 CEST 2014


Hi Duncan,

Thanks for trying to help. Sorry for not being clear.
The string I'd like to get is 'AARSD1'
It can be followed or preceded by white space or // or nothing

so, from test <- c('AARSD11','AARSD1-','AARSD1//','AARSD1 //','//AARSD1','AARSD1');

I want to match only 'AARSD1//','AARSD1 //','//AARSD1','AARSD1'

Thanks,
Lin
 
----------------------------------------
> From: dulcalma at bigpond.com
> To: baccts at hotmail.com; r-help at r-project.org
> Subject: RE: [R] regular expression help
> Date: Fri, 27 Jun 2014 10:59:29 +1000
>
> Hi
>
> You only have a vector of length 5 and I am not quite sure of the string you
> are testing
> so try this
>
> grep('[/]*\\<AARSD1\\>[/]*',test)
>
> Duncan
>
> Duncan Mackay
> Department of Agronomy and Soil Science
> University of New England
> Armidale NSW 2351
> Email: home: mackay at northnet.com.au
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
> Behalf Of C Lin
> Sent: Friday, 27 June 2014 10:05
> To: r-help at r-project.org
> Subject: [R] regular expression help
>
> Dear R users,
>
> I need to match a string. It can be followed or preceded by whitespace or //
> or nothing.
> How do I code it in R?
>
> For example:
> test <- c('AARSD11','AARSD1-','AARSD1//','AARSD1 //','//AARSD1');
> grep('AARSD1(\\s*//*)',test);
>
> should return 3,4,5 and 6.
>
> Thanks in advance for your help.
>
> Lin
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