Re: Zero-width assertions fail with split

[merlyn]

De Morgan is kicking your hiney.

It's working as I would expect. You are asking to split on commas that have neither dashes before NOR dashes afterwards, as in "the delimiter is NOT dashes ahead AND a comma AND NOT dashes afterwards". That's the only time the split regex would match. Dashes on either side would prevent the comma from being considered. Your experimental results are borne out.

And simply splitting on commas would give you the list you want, so you'll have to show an example where simply splitting on commas doesn't do it.

[Ovid]

That makes sense and, as noted, the results aren't entirely suprising, though I confess I struggled with it. Is there some simple way of getting the split behavior to do what I want?

[hv]

You want "not both preceded and followed by TOKEN", which is equivalent to "either not preceded by TOKEN, or not followed by TOKEN", and that we can do:

  my $split  = qr/
    (?<!$token) ,
  |
    , (?!$token)
  /x;

Hugo

[gargle]

Hi,

It may be silly, but, doesn't this do what you want?

perl -e '$a = "1,2,---0---,3,4";@f=split ",",$a;map { print $_."\n"}
 @f'