[R] Dividing one column of form xx-yy into two columns, xx and yy

[Gabor Grothendieck]

If you are willing to use an outside utility, tr, and you are using
UNIX then you can pipe the input through it so read.csv sees all the
dashes as commas:

> cat("A,B-C,D
+ 1,2-3,4
+ 5,6-7,8
+ ", file = "dashcomma.dat")
>
> read.csv(pipe("tr - , < dashcomma.dat"))
  A B C D
1 1 2 3 4
2 5 6 7 8

On Windows tr is available from Duncan Murdoch's Rtools distribution.
(google to find it).



On Mon, Feb 8, 2010 at 6:31 PM, ZeMajik <zemajik at gmail.com> wrote:
> I have a data set where one column consists of two numerical factors,
> separated by a "-".
> So my data looks something like this:
>
> 43-156
> 43-43
> 1267-18
> .
> .
> .
>
> There are additional columns consisting of single factors as well, so
> reading the csv file (where the data is stored) with the sep="-" addition
> won't work since the rest of the factors are separated by commas.
> So first of all, is there any way to import a file which is separated by ","
> OR "-"?
>
> If this is not possible, does anyone have any ideas how I could go about to
> separate these? I could use a text editor to replace the - with , and
> import, but I would prefer doing this inside of R so that making a script
> could be used in the future.
>
> Just to clarify, I would like the above to turn out as two separate columns
> (or vectors) where the first in this would be (43,43,1267,....) and the
> second (156,43,18,.....)
> The dataset is rather large, with a few hundred thousand lines, so it would
> be preferable to keep resource intensive methods to a minimum if possible.
>
> Thanks in advance!
> Mike
>
>        [[alternative HTML version deleted]]
>
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