Re^3: map to hash of arrays

[dpuu]

in reply to Re^2: map to hash of arrays
in thread map to hash of arrays

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;
    }
  }

[emilford]

Why would I want to use this over ccn's solution? Is it a matter of efficiency?

[dpuu]

I don't think there's any good reason. ccn assumes, obviously correctly, that the entire data is available in a single string. I didn't realise that. Also, I'd be very tempted to use the /x modifier, and insert some comments.

[emilford]

That's the part I'm confused about, however. The data is not available in a single string. If I write the output to file, everything is broken down into seperate lines.