Yet another way to do it...

my @array = ({doc1=>2345}, {doc2=>1234}, {doc3=>5678}, {doc4=>4567});
my %hash = map { %{$_} } @array;
my @sorted = sort { $hash{$a} <=> $hash{$b} } keys %hash;
print "@sorted\n";
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Update: Removed each from my %hash = map { each %{$_} } @array;.