[R] regular expressions : extracting numbers

[Romain Francois]

Bonjour David,

What about one of these :

R> gsub( "[^[:digit:]]", "", x )

or using perl regular expressions:

R> gsub( "\\D", "", x, perl = T )

Cheers,

Romain

GOUACHE David wrote:
> Hello all,
>
> I have a vector of character strings, in which I have letters, numbers, and symbols. What I wish to do is obtain a vector of the same length with just the numbers.
> A quick example -
>
> extract of the original vector :
> "lema, rb 2%" "rb 2%" "rb 3%" "rb 4%" "rb 3%" "rb 2%,mineuse" "rb" "rb" "rb 12" "rb" "rj 30%" "rb" "rb" "rb 25%" "rb" "rb" "rb" "rj, rb"
>
> and the type of thing I wish to end up with :
> "2" "2" "3" "4" "3" "2" "" "" "12" "" "30" "" "" "25" "" "" "" ""
>
> or, instead of "", NA would be acceptable (actually it would almost be better for me)
>
> Anyways, I've been battling with gsub() and things of the sort, but I'm drowning in the regular expressions, despite a few hours of looking at Perl tutorials...
> So if anyone can help me out, it would be greatly appreciated!!
>
> In advance, thanks very much.
>
> David Gouache
> Arvalis - Institut du Végétal
> Station de La Minière
> 78280 Guyancourt
> Tel: 01.30.12.96.22 / Port: 06.86.08.94.3


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