Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi all, Been a few years since I've perl'd, and I can't remember the solution to the following: What is the shorthand way to say: 
foreach (@biglonglist) {
  if (/(thing1)misc stuff(thing2)random garbage(thing3)/) {
    $x->{a} = $1;
    $x->{b} = $2;
    $x->{c} = $3;
  }
}

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I can't use split because the junk data in between my valid matches isn't consistant. I know I will always have exactly three matches. I thought that the backreferences were returned in a list, but I can't remember what that is. Thanks! f.

Replies are listed 'Best First'.
Re: pattern matching and return values
by davido (Cardinal) on Jul 18, 2004 at 05:20 UTC

    Here's an example using a simple hash (instead of a hash-ref as you're dealing with). This solution declares the hash, and then assigns to it using a hash slice. It has limitations. For example, you have to know up front how many items you're capturing. But it works pretty well. 

    my $string = "This is that is other is";
my %hash;
if ( @hash{'a', 'b', 'c'} 
       = $string =~ m/(This).+(that).+(other).+/ ) {
    print "$_ = $hash{$_}\n" foreach keys %hash;
}

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    As for how to "do" a hash slice given a hash-ref, it's like this: 

    @{$x}{'a', 'b', 'c'} = ( list );

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    (...that is, if memory serves.)

    UPDATE: I just realized, this is my 1000th post! Enjoy!


    Dave

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[d/l]
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      Congratulations!
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Re: pattern matching and return values
by saintmike (Vicar) on Jul 18, 2004 at 05:23 UTC
    If you put the match operation in list context, you can gobble up the matched items: 
    if( my($a, $c) = $string =~ /(a).*(c)/ ) {
    print "a=$a c=$c\n";
}

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    To store them in a hash,use a hash slice to assign them: 
    @result{"a","b"} = $string =~ /(a).*(c)/;

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[d/l]
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      great, thanks f.
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Re: pattern matching and return values
by tachyon (Chancellor) on Jul 18, 2004 at 05:43 UTC
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      lame but fun; don't follow this idiom|t.

      use Data::Dumper;
my $stuff = 'ASDFZXCV S;JL KJQWER QWER ZXCVO ;QLKWERQ JKL;JAPS';
my %hash;
my @keys = qw( asdf qwer jkl; );

@hash{@keys} = $stuff =~ / (asdf) .*? (qwer) .*? (jkl;) /gix;

print Dumper \%hash;

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[d/l]

        I'm with you there! Just because you can does not mean you should.

        cheers

        tachyon

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Re: pattern matching and return values
by Anonymous Monk on Jul 18, 2004 at 05:12 UTC
    Sorry, might be a little unclear: I'm looking for a shorthand way to assign the backreferences to a hash.

    thks again.
    f.
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