[R] replace last 3 characters of string

Dirk Eddelbuettel edd at debian.org
Mon Apr 4 01:39:14 CEST 2011

On Mon, Apr 04, 2011 at 01:39:34AM +0200, Bert Jacobs wrote:
> I would like to replace the last tree characters of the values of a certain
> column in a dataframe.
> This replacement should only take place if the last three characters
> correspond to the value "/:/" and they should be replaced with ""(blank)
> I cannot perform a simple gsub because the characters /:/ might also be
> present somewhere else in the string values and then they should not be
> replaced.

Keep reading up on regular expressions, this tends to pay off. Here we
use the fact that you can achor a regexp to the end of a string:

R> aString <- "abc:def:::"
R> gsub(":::$", "", aString)
[1] "abc:def"

Hth, Dirk

Three out of two people have difficulties with fractions.

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