[R] split a string a keep the last part

Marc Schwartz
Thu, 28 Aug 2014 18:08:22 -0000

On Aug 28, 2014, at 12:41 PM, Jun Shen <jun.shen.ut at gmail.com> wrote:

> Hi everyone,
>
> I believe I am not the first one to have this problem but couldn't find
a
> relevant thread on the list.
>
> Say I have a string (actually it is the whole column in a data frame) in a
> format like this:
>
> test<- 'AF14-485-502-89-00235'
>
> I would like to split the test string and keep the last part. I think I can
> do the following
>
> sub('.*-.*-.*-.*-(.*)','\\1', test)
>
> to keep the fifth part of the string. But this won't work if other
strings
> have more or fewer parts separated by '-'. Is there a general way
to do it?
> Thanks.
>
> Jun


Try this:

test <- 'AF14-485-502-89-00235'

> sub("^.*-(.*)$", "\\1", test)
[1] "00235"


test <- 'AF14-485-502-89-00235-1234'

> sub("^.*-(.*)$", "\\1", test)
[1] "1234"


Another option:

> tail(unlist(strsplit(test, "-")), 1)
[1] "1234"


Regards,

Marc Schwartz