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Re^2: creating a regular expression's alternation dynamically?

by integral (Hermit)
on Aug 06, 2004 at 14:39 UTC ( #380572=note: print w/ replies, xml ) Need Help??


in reply to Re: creating a regular expression's alternation dynamically?
in thread creating a regular expression's alternation dynamically?

In the join, you might want to map quotemeta over @list so that any meta-chars (particulary |) get escaped.

Also you have to be careful that none of the strings are prefixes of another string, otherwise you'll find that ordering is significant in an alternation.

--
integral, resident of freenode's #perl


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Re^3: creating a regular expression's alternation dynamically?
by mifflin (Curate) on Aug 06, 2004 at 17:27 UTC
    yep, good point, thanks!
    use strict; use warnings; # create alternation my @list; while (<DATA>) { chomp; push @list, $_; } my $regex = '^(' . join('|', map {quotemeta} @list) . ')$'; my $s = 'huey'; print "regex = $regex\n"; print "match:\t$1\n" if $s =~ m/$regex/; __DATA__ huey de|wey louie
    output is...
    # perl test.pl regex = ^(huey|de\|wey|louie)$ match: huey

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