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Re: map to hash of arrays

by dpuu (Chaplain)
on Jul 22, 2004 at 21:13 UTC ( #376719=note: print w/replies, xml ) Need Help??


in reply to map to hash of arrays

It is obviously possible, but it would not be "nifty". In fact, I think it'd be worse solution than just using a C<for> loop in the first place. You just have to build a temportary hash off to the side. But if you're going to build a tmp hash, then you might as well just build the real one.

--Dave
Opinions my own; statements of fact may be in error.

Replies are listed 'Best First'.
Re^2: map to hash of arrays
by emilford (Friar) on Jul 26, 2004 at 14:18 UTC
    That's my issue. I want to build the real hash of arrays without the need of a temporary one. I'm just not sure how to go about doing that.
[reply]
      Use a while loop, not a map: 
        my %hash;
  my $key;
  while (<>) {
    /\S+ : (\S+)/ or die "unexpected line format: $_";
    my $value = $1;
    if (defined $key) {
      push @{ $hash{$key} }, $value;
      undef $key;
    else {
      $key = $value;
    }
  }

      [download]
      --Dave
      Opinions my own; statements of fact may be in error.
[reply]
[d/l]
        Why would I want to use this over ccn's solution? Is it a matter of efficiency?
[reply]

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