in reply to Re: Re: Re: $_ works, $my_variable doesn't?
in thread $_ works, $my_variable doesn't?

my @strings = qw(
    aaaaa
    eeeee
    iiiii
    abcde
    aeiou
    bdfhj
);

my %regexes = (
    alternation => qr/a|A|e|E|i|I|o|O|u|U/,
    class       => qr/[AaEeIiOoUu]/
);

foreach my $string (@strings)
{
    print "$string:\n";
    while (my ($k, $r) = each %regexes)
    {
        print "\t$k - " . ($string =~ /$r/ ? 'YES' : 'NO') . $/;
    }
}
---------------
aaaaa:
        alternation - YES
        class - YES
eeeee:
        alternation - YES
        class - YES
iiiii:
        alternation - YES
        class - YES
abcde:
        alternation - YES
        class - YES
aeiou:
        alternation - YES
        class - YES
bdfhj:
        alternation - NO
        class - NO

[download]

Please give me a counter-case. As far as I can tell, the two regexes are identical, save that the alternation one is slower.

------
We are the carpenters and bricklayers of the Information Age.

Then there are Damian modules.... *sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon. - flyingmoose

Replies are listed 'Best First'.
Re: Re: Re: Re: Re: $_ works, $my_variable doesn't?
by duff (Parson) on Mar 30, 2004 at 14:28 UTC
    The OP was looking for strings that contain all of the vowels. Your code doesn't do that.

    duff

[reply]
      In my defense, neither did the code I was referring to.

      That is an interesting question - is there a way to have a regex take a character class and determine if the string contains all the characters in the class?

      ------
      We are the carpenters and bricklayers of the Information Age.

      Then there are Damian modules.... *sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon. - flyingmoose

[reply]

        Yes, the original mistake was mine. I have since updated that node. I don't know any slick way of putting it all in one character class, though with lookahead it could be wedged into one regex.

        Update: here's my first shot at a lookahead version:

        my @strings = qw(
    aaaaa
    eeeee
    iiiii
    abcde
    aeiou
    bdfhj
);

my $range = 'AaEeIiOoUu';
my $alt   = join '|', split //, $range;

my %regexes = (
    alternation => qr/$alt/,
    class       => qr/[$range]/,
    lookahead   => qr/([$range])((?!\1)[$range])((?!\2)[$range])((?!\3
+)[$range])((?!\4)[$range])/,
);

foreach my $string (@strings)
{
    print "$string:\n";
    while (my ($k, $r) = each %regexes)
    {
        print "\t$k - " . ($string =~ /$r/ ? 'YES' : 'NO') . $/;
    }
}

        [download]

        And the output:

        aaaaa:
        alternation - YES
        class - YES
        lookahead - NO
eeeee:
        alternation - YES
        class - YES
        lookahead - NO
iiiii:
        alternation - YES
        class - YES
        lookahead - NO
abcde:
        alternation - YES
        class - YES
        lookahead - NO
aeiou:
        alternation - YES
        class - YES
        lookahead - YES
bdfhj:
        alternation - NO
        class - NO
        lookahead - NO

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