Re^3: Common hash keys

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Re^4: Common hash keys by massa (Hermit) on Jun 07, 2008 at 13:34 UTC
Maybe `my @keys_in_commmon = grep $hashref1->{$_}, keys %$hashref2;` [download] would've sufficed?? If you just have to determine if they have keys in common, `if( grep $hashref1->{$_}, keys %$hashref2 ) { ... }` [download] would do the trick...	[reply] [d/l] [select]
Re^5: Common hash keys by Anonymous Monk on Jun 08, 2008 at 06:56 UTC
I would say `my @keys_in_commmon = grep``exists``($hashref1->{$_}), keys %$hashref2;` to avoid autovivification.	[reply] [d/l] [select]
Re^6: Common hash keys by parv (Parson) on Jun 08, 2008 at 08:29 UTC
massa's code does not actually cause autovivification (perl 5.8.8) ... `use warnings; use strict; use Data::Dumper; my %p; my %q = ( 1 => undef ); print Dumper( 'before', \%p ); my $r = grep $p{ $_ }, keys %q; print Dumper( 'after', \%p );` [download] ... I was also suspicious of autovivification but had to test that myself.	[reply] [d/l]
Re^6: Common hash keys by throop (Chaplain) on Jun 08, 2008 at 13:31 UTC
The `exists` test is so that the case where a key has undef as a value, not to aviode auto vivification. Undef itself cannot be a key in a hash. But '0' and '' can.	[reply]
Re^7: Common hash keys by Porculus (Hermit) on Jun 15, 2008 at 17:30 UTC