list files ignoring the case option

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch 
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Sundar 
Dorai-Raj
Sent: Thursday, November 04, 2004 6:39 AM
To: ramasamy at cancer.org.uk
Cc: R-help
Subject: Re: [R] list files ignoring the case option



Adaikalavan Ramasamy wrote:

Sorry if this is a question more on regular expressions. I 

am dealing

with several files which have been badly named. For example 

the files

are given either the extensions txt, TXT or Txt. I wish to 

select all

those files ending with 'txt' ignoring case.

Here is how I would do it in bash (Redhat FC2) :

   touch  a1.txt  a2.TXT  a3.Txt  txt.control  TXT.control
   ls -1 | grep -i "txt$"


Here is how I am currently doing it in R

   a <- list.files(all.files=T)
   grep( "txt$", a, ignore.case=T, value=T )


Is it possible for me to modify the following line to include ignore
case option ?

   a <- list.files( pattern="txt$" )

Thank you.

Regards, Adai

Not much of a regexpr guy myself, but the following should work:

list.files(pattern = "[tT][xX][tT]$")

There's probably a better answer though.

--sundar