[R] Numbers in a string

[Petr Savicky]

On Wed, Dec 15, 2010 at 01:29:16PM -0500, David Winsemius wrote:
> 
> On Dec 15, 2010, at 6:01 AM, Nick Sabbe wrote:
> 
> >Hi Felipe,
> >
> >gsub("[^0123456789]", "", "AB15E9SDF654VKBN?dvb.65")
> >results in "15965465".
> >Would that be what you are looking for?
> 
> 
> I tried figuring out how to do this from a more positive perspective,  
> meaning finding a regular expression function that did not require  
> negating the desired elements, but the best I could do was make a  
> function that accepted a pattern and then hid the underlying negation:
> 
> > pullchar <- function(txt, patt){
>          if(grepl("\\[", patt)){pattn <- sub("\\[", "\\[\\^", patt)}  
> else{
>                                 pattn<- paste("[^",patt,"]", sep="")}
>          gsub(pattn, "", txt)  #return   }
> 
> > pullchar("AB15E9SDF654VKBN?dvb.65", "ABD")
> [1] "ABDB"
> > pullchar("AB15E9SDF654VKBN?dvb.65", "[A-Z]")
> [1] "ABESDFVKBN"
> > pullchar("AB15E9SDF654VKBN?dvb.65", "[0-9]")
> [1] "15965465"
> 
> Still learning regex so if there is a "positive" strategy I'm all  
> ears. ...er, eyes?

One of the suggestions in this thread was to use an external program.
A possible solution without negation in Perl is

  @a = ("AB15E9SDF654VKBN?dvb.65" =~ m/[0-9]/g);
  print @a, "\n";
  15965465

or

  @a = ("AB15E9SDF654VKBN?dvb.65" =~ m/[.0-9]+/g);
  print join(" ", @a), "\n";
  15 9 654 .65

Do you mean something in this direction?

Petr Savicky.