[ILUG] Perl regex question

[Padraig Brady]

Rory Winston wrote:
> Hi
> 
> I have a question re: a regex that has had me stumped. I have a CGI script
> that generates a string of concatenated user ids, such as "1|2|86|907|7|"
> etc. I had a regex that extracts the uids like so:
> 
> print("id=$1\n") while ( $id_string =~ /(\d+)|/g );
> 
> But this doesnt work - I always get an extraneous (empty) match for every
> id, and an extra empty match at the end! Is this because it matches the '|'
> character second time round or something?  it does work if I do:
> 
> print("id=$1\n") while ( $id_string =~ /(\d+)(|)/g );
> 
> I know, I know - RTFM for regexes - I have a copy of Friedl's "Mastering
> Regular Expressions" on my shelf that I'm going to get around to reading one
> of these days, but until then, can anyone shed any light?

1. | are special in re's so you probably want to escape it like \|
2. This is simple enough not to require a re, see split()
3. I don't know perl so here's the python equivalent:

for id in "1|2|86|907|7".split("|"):
     print "id=" + id

Padraig.