R help - Mar 2014 - automatically replacing the third period with a break

I've got a dataset with really long column names (e.g.,
CYJ.OSU.OAV.UJC.BUT.RDI). What I'd like to do is replace the fourth period
with a break ("\n") so that when it plots, it will not run off the
page.
Here's what I've got so far:

#### create fake names function
fake.names = function(x){
    paste0(LETTERS[sample(1:26,3)], collapse="")
}
#### create the fake names
fake = paste0(unlist(lapply(1:6, fake.names)), collapse=".")

#### replace fourth period with \n
gsub("[[:alnum:]]\\.[[:alnum:]]+\\.[[:alnum:]]+\\.[[:alnum:]]+\\.",
"[[:alnum:]]\\.[[:alnum:]]+\\.[[:alnum:]]+\\.[[:alnum:]]+\n",fake)

which results in something like:

"TW[[:alnum:]].[[:alnum:]]+.[[:alnum:]]+.[[:alnum:]]+\nNQJ.VSI"

Any ideas on how to make it replace that?

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On Tue, Mar 18, 2014 at 12:43 PM, Dustin Fife <fife.dustin@gmail.com>
wrote:
> I've got a dataset with really long column names (e.g.,
> CYJ.OSU.OAV.UJC.BUT.RDI). What I'd like to do is replace the fourth
period
> with a break ("\n") so that when it plots, it will not run off
the page.
> Here's what I've got so far:
>
> #### create fake names function
> fake.names = function(x){
>     paste0(LETTERS[sample(1:26,3)], collapse="")
> }
> #### create the fake names
> fake = paste0(unlist(lapply(1:6, fake.names)), collapse=".")
>
>
Backreferences

cat(
  gsub("(([[:alnum:]]+\\.){3})([[:alnum:]]+)\\.",
             "\\1\\2\n",
              fake
          )
)

That is, match three word/period sequences, match a word, match a period,
and output the first two things.

  -thomas

-- 
Thomas Lumley
Professor of Biostatistics
University of Auckland

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