Re: Getting rid of a temporary variable in AoH

Once the @fields array is declared inside the loop, you can safely destroy it:

while ( my $line = <DATA> ) {
    chomp $line;
    my @fields = qw( login      uid   gid       name           home   
+   shell );
    my @items  =
        $line =~ /^([\-\w]+):x:(\d+):(\d+):([\-\w\s\(\)\,]*):([\w\/]+)
+:([\w\/]+)$/
            or die "Malformed input [$line]";

    push @users, {};
    $users[-1]{ shift @fields } = shift @items while @fields;
}
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Comment on Re: Getting rid of a temporary variable in AoH Download Code

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Re^2: Getting rid of a temporary variable in AoH by AnomalousMonk (Archbishop) on Jun 12, 2013 at 02:58 UTC
A variation (imagine the `my $datum = shift @data` is reading a file; no need to create `@fields` array each time through loop; state only available with 5.10+; either version works the same): >perl -wMstrict -MData::Dump -lE "my @data = ( 'foo 123 %^&', 'huggle 9876 @', 'ab 55555 !@$%^&', ); ;; my @users; while (my $datum = shift @data) { # use constant FIELDS => qw( alphas digits stuff) +; state $fields = [ qw( alphas digits stuff) ] +; my @items = $datum =~ m{ ([[:alpha:]]+) \s+ (\d+) \s+ ([^[:alpha:]\ +d]+) }xms; # @{ $users[@users] }{ FIELDS() } = @items; @{ $users[@users] }{ @$fields } = @items; } ;; dd \@users; " [ { alphas => "foo", digits => 123, stuff => "%^&" }, { alphas => "huggle", digits => 9876, stuff => "\@" }, { alphas => "ab", digits => 55555, stuff => "!\@\$%^&" }, ] [download]	[reply] [d/l] [select]

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Re^2: Getting rid of a temporary variable in AoH
by AnomalousMonk (Archbishop) on Jun 12, 2013 at 02:58 UTC

A variation (imagine the my $datum = shift @data is reading a file; no need to create @fields array each time through loop; state only available with 5.10+; either version works the same):

>perl -wMstrict -MData::Dump -lE
"my @data = (
   'foo 123 %^&',  'huggle 9876 @*',   'ab 55555 !@$%^&',
   );
 ;;
 my @users;
 while (my $datum = shift @data) {
   # use constant FIELDS => qw(   alphas        digits          stuff)
+;
   state $fields = [ qw(        alphas        digits          stuff) ]
+;
   my @items = $datum =~ m{ ([[:alpha:]]+) \s+ (\d+) \s+ ([^[:alpha:]\
+d]+) }xms;
   # @{ $users[@users] }{ FIELDS() } = @items;
   @{ $users[@users] }{ @$fields } = @items;
   }
 ;;
 dd \@users;
"
[
  { alphas => "foo", digits => 123, stuff => "%^&" },
  { alphas => "huggle", digits => 9876, stuff => "\@*" },
  { alphas => "ab", digits => 55555, stuff => "!\@\$%^&" },
]
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