Re^2: Getting Max Value from Different Hashes

Corion, your method is straightforward but suffers because it makes a copy of every value at once. You could still use max() but only have one hash copy present at a time just by switching to reduce().

my @hashes = ( $hash_w, $hash_x, $hash_y, $hash_z );
my $max = max( values %{shift @hashes } );
$max = reduce { max( $_[0], values %{$_[1]} ) }
    @hashes;
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Re^3: Getting Max Value from Different Hashes by polettix (Vicar) on Aug 01, 2005 at 15:56 UTC
I hope that the OP was not seriuos about the efficiency issue - this is why such an optimisation over 4 values seems weird to me :) Flavio perl -ple'$_=reverse' <<<ti.xittelop@oivalf Don't fool yourself.	[reply]
Re^4: Getting Max Value from Different Hashes by diotalevi (Canon) on Aug 01, 2005 at 16:03 UTC
That isn't over four values, that's over four collections each of unknown size. I was seriously considering adding this other method just because the collection size was unknown. This moves from collection-at-a-time to element-at-a-time. `my @collections = ...; my $first_collection = shift @collections; keys %$first_collection; my ( undef, $max ) = each %$first_collection; while ( my ( undef, $elt ) = each %$first_collection ) { if ( $elt > $max ) { $max = $elt; } } for my $collection ( @collections ) { keys %$collection; while ( my ( undef, $elt ) = each %$collection ) { if ( $elt > $max ) { $max = $elt; } } }` [download]	[reply] [d/l]
Re^5: Getting Max Value from Different Hashes by polettix (Vicar) on Aug 01, 2005 at 16:13 UTC
Maybe the OP changed the specs on the fly, but I read (bold mine): Given 4 distinct hashes with only one key-value The only uncertainty is in the fact that this only one key-value is present or not. Flavio perl -ple'$_=reverse' <<<ti.xittelop@oivalf Don't fool yourself.	[reply]