R help - Oct 2005 - getting last 2 charcters of a string, other "text" functions?

I wish to obtain the right-most n characters of a character string?  What is the
appropriate function?


		
---------------------------------

	[[alternative HTML version deleted]]

?nchar
?substr

rightmost <- function(x, y){substr(x, start=nchar(x) - (y - 1), 
stop=nchar(x))}

 > x <- c("asfef", "qwerty", "yuiop[",
"b", "stuff.blah.yech")

 > rightmost(x, 2)
[1] "ef" "ty" "p[" "b"  "ch"

 > rightmost(x, 3)
[1] "fef" "rty" "op[" "b"  
"ech"

t c wrote:
> I wish to obtain the right-most n characters of a character string?  What
is the appropriate function?
> 
> 
> 		
> ---------------------------------
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
> 
-- 
Chuck Cleland, Ph.D.
NDRI, Inc.
71 West 23rd Street, 8th floor
New York, NY 10010
tel: (212) 845-4495 (Tu, Th)
tel: (732) 452-1424 (M, W, F)
fax: (917) 438-0894

t c wrote:
> I wish to obtain the right-most n characters of a character string?  What
is the appropriate function?
> 
See ?nchar ?substr

k <- 2
x <- "abcdef"
nc <- nchar(x)
substr(x, nc - k + 1, nc)

HTH,

--sundar

gsub(".*(..)$", "\\1", "i only want the last two
characters")

This is only a matter of finding the right regular expression. Use Google to
find a good tutorial on them.

Carlos J. Gil Bellosta
http://www.datanalytics.com


Quoting t c <quantpm at yahoo.com>:
> I wish to obtain the right-most n characters of a character string?  
> What is the appropriate function?
>
>
>
> ---------------------------------
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>

"t c" <quantpm at yahoo.com> wrote in message
news:20051031153755.80990.qmail at
web35006.mail.mud.yahoo.com...
> I wish to obtain the right-most n characters of a character string?  What
is the appropriate function?

substr will work:
> x <- c("abcd", "xyz")
> N <- 2
> substr(x, nchar(x)-N+1, nchar(x))
[1] "cd" "yz"
> N <- 3
> substr(x, nchar(x)-N+1, nchar(x))
[1] "bcd" "xyz"

efg

t c wrote:
>I wish to obtain the right-most n characters of a character string?  What is
the appropriate function?
>  
>
You could make one yourself:

rightmostn <- function(x, n){
  res <- substr(x, nchar(x)-n+1, nchar(x))
  return(res)
}
magic <- "hocuspocus"
rightmostn(magic, 5)
[1] "pocus"

HTH,
Tobias
>
>		
>---------------------------------
>
>	[[alternative HTML version deleted]]
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>
>
>  
>

Note that this one can be slightly simplified by using sub instead of gsub
(since you only will have one match anyways) and the $ is not needed
since .* will consume the maximal matching string:

sub(".*(..)", "\\1", mystring)


On 10/31/05, Carlos J. Gil Bellosta <cgb at datanalytics.com>
wrote:
> gsub(".*(..)$", "\\1", "i only want the last two
characters")
>
> This is only a matter of finding the right regular expression. Use Google
to
> find a good tutorial on them.
>
> Carlos J. Gil Bellosta
> http://www.datanalytics.com
>
>
> Quoting t c <quantpm at yahoo.com>:
>
> > I wish to obtain the right-most n characters of a character string?
> > What is the appropriate function?
> >
> >
> >
> > ---------------------------------
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
> >
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>