[R] Working with regular expression

arun smartpink111 at yahoo.com
Fri Jan 18 23:09:02 CET 2013

Not sure what format you wanted the dates: 
gsub("^\\w+ ","",gsub("[_]"," ",Text)) 
#[1] "May 09 2009" "01-01-2001" 

#Another way is: 
gsub("^\\w+ |\\w+_","",Text) 
#[1] "May 09 2009" "01-01-2001" 
res<- gsub("^\\w+ |\\w+_","",Text) 
res1<-c(as.Date(res[grep(" ",res)],format="%b %d %Y"), as.Date(res[-grep(" ",res)],format="%m-%d-%Y")) 
#[1] "2009-05-09" "2001-01-01" 

----- Original Message -----
From: Christofer Bogaso <bogaso.christofer at gmail.com>
To: r-help <r-help at r-project.org>
Sent: Friday, January 18, 2013 3:11 PM
Subject: [R] Working with regular expression

Hello again,

I was trying to extract the date element from a character vector using
Regular expression. Below is a sample what I was trying to do:

> Text <- c("asdf May 09 2009", "dsaf_01-01-2001")
> gsub("[a-zA-Z_]", "", Text)
[1] "  09 2009"  "01-01-2001"

I basically have a long text and the task is to extract the date
element. My above strategy failed because I can not extract the month
for the first element.

Can somebody help me out?

Thanks and regards,

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