[R] list files ignoring the case option

[Sundar Dorai-Raj]

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