[R] Q about strsplit and regexp

[John Fox]

Dear Andy,

This is something that I sometimes want to do, so I have a little utility
that trims blanks and tabs from the beginnings and ends of strings:

trim.ws <- function(text) gsub("^[\ \t]", "", gsub("[\ \t]*$", "", text))

Regards,
 John

--------------------------------
John Fox
Department of Sociology
McMaster University
Hamilton, Ontario
Canada L8S 4M4
905-525-9140x23604
http://socserv.mcmaster.ca/jfox 
-------------------------------- 

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Liaw, Andy
> Sent: Wednesday, October 20, 2004 7:16 AM
> To: R-Help
> Subject: [R] Q about strsplit and regexp
> 
> Dear R-help,
> 
> This one is probably a piece of cake for regexp masters.  I'd 
> like to split a character vector (for simplicity, say of 
> length one for now) that contains fields that are delimited 
> by arbitrary number of white spaces (e.g., "  a b c ").  How 
> do I get the character vector that contain the fields?  In 
> the example I gave, I've tried:
> 
> > strsplit("  a b    c ", " +")
> [[1]]
> [1] ""  "a" "b" "c"
> 
> I do not want that empty character in the beginning, but 
> couldn't figure out how to strip the starting white spaces, 
> other than something ugly like:
> 
> > strsplit(sub("^ +", "", "  a b    c "), " +")
> [[1]]
> [1] "a" "b" "c"
> 
> Can some kind soul point me to a simpler way?  TIA!!
> 
> Best,
> Andy
> 
> Andy Liaw, PhD
> Biometrics Research      PO Box 2000, RY33-300     
> Merck Research Labs           Rahway, NJ 07065
> andy_liaw <at> merck.com          732-594-0820
> 
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