Re: referring to anonymous array in value of a hash in array context...

~~Unless the array is huge,~~ it's easier to access the values directly through the for loop

$hash{"array"} = ['a','b','c','d','e'];
print for @{ $hash{ array } };

a
b
c
d
e
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Re^2: referring to anonymous array in value of a hash in array context... by Fletch (Bishop) on Jul 08, 2004 at 01:34 UTC
Actually the size of the array shouldn't matter because when `foreach` gets a real array perl will be smart and won't expand things in place (it uses an iterator over the AV* behind the scenes which all happens in C underneath). `$ perl -MBenchmark=timethese -e <<'EOC' $a = [ 0 ..5_000 ]; timethese( 2_000, { index => sub { for( my $i = 0; $i <= $#{ $a }; $i++ ) { $b = $a->[ +$i] } }, iterator => sub { for( @{ $a } ) { $b = $_ } } } ) EOC Benchmark: timing 2000 iterations of index, iterator... index: 27 wallclock secs (21.21 usr + 0.02 sys = 21.23 CPU) @ 94 +.21/s (n=2000) iterator: 6 wallclock secs ( 5.39 usr + 0.00 sys = 5.39 CPU) @ 37 +1.06/s (n=2000)` [download]	[reply] [d/l] [select]

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Re^2: referring to anonymous array in value of a hash in array context...
by Fletch (Bishop) on Jul 08, 2004 at 01:34 UTC

Actually the size of the array shouldn't matter because when foreach gets a real array perl will be smart and won't expand things in place (it uses an iterator over the AV* behind the scenes which all happens in C underneath).

$ perl -MBenchmark=timethese -e <<'EOC'
$a = [ 0 ..5_000 ];
timethese( 2_000,
  { index => sub { for( my $i = 0; $i <= $#{ $a }; $i++ ) { $b = $a->[
+$i] } },
    iterator => sub { for( @{ $a } ) { $b = $_ } } } )
EOC
Benchmark: timing 2000 iterations of index, iterator...
     index: 27 wallclock secs (21.21 usr +  0.02 sys = 21.23 CPU) @ 94
+.21/s (n=2000)
  iterator:  6 wallclock secs ( 5.39 usr +  0.00 sys =  5.39 CPU) @ 37
+1.06/s (n=2000)
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