[R] Doubt about pattern

[Henrik Bengtsson]

Hi. 

1. A period in a pattern (as you wrote) means that you want to match
*any* character. You need to escape the period, i.e. "\\.", or
alternatively use the "[<set>]" indicator where <set> is all the
characters you allow at that position, i.e. "[.]". (I prefer the
latter because in is more readable and you don't have the \\ or \
problem when cut'n'pasting.)

2. To match the end of string use "$".

Thus, you want to do

 files <- dir(pattern="*[.]sens$")

To match filenames that ends with ".sens". 

This is how regexpr(), gsub() and friends all work.

Cheers

Henrik Bengtsson

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of 
> Marcelo Luiz de Laia
> Sent: den 29 januari 2004 15:33
> To: r-help at stat.math.ethz.ch
> Subject: [R] Doubt about pattern
> 
> 
> Hi All,
> 
> I have a very simple problem. I have several files in a same 
> directory. I would like to send for an object only the files 
> that finish in ".sens.". I execute the command below,
> 
> files <- dir(pattern="*.sens")
> 
> but it includes all of the files that have "sens", 
> independent of they be in the end or in the middle of the 
> name of the file. How could I solve this? I sought in the 
> html_help but I didn't find similar to this.
> 
> My files
> 
> "script_sens.txt", "Sen_155_01_R1.sens", 
> "Sen_155_01_R2.sens", "Sen_155_01_R3.sens", 
> "Sen_155_02_R1.sens", "Sen_155_02_R2.sens", 
> "Sen_155_02_R3.sens", "Sen_155_03_R1.sens", 
> "Sen_155_03_R2.sens", "Sen_155_03_R3.sens",
"tome2sens_time1sens.txt"
> 
> Tahnks very much
> 
> -- 
> Marcelo Luiz de Laia, M.Sc.
> Dep. de Tecnologia, Lab. Bioquímica e de Biologia Molecular 
> Universidade Estadual Paulista - UNESP Via de Acesso Prof. 
> Paulo Donato Castelane, Km 05 14.884-900 - Jaboticabal, SP, Brazil
> PhoneFax: 16 3209-2675/2676/2677 R. 202/208/203 (trab.)
> HomePhone: 16 3203 2328 - www.lbm.fcav.unesp.br - mlaia at yahoo.com
> 
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