my $data = ; use Benchmark "cmpthese"; cmpthese(10_000, { "reversed" => sub { my %hash; my $reversed_data = reverse($data); $hash{reverse($2)} = reverse($1) while $reversed_data =~ /\s*([^=]+?)\s*=\s*(\w+)/g; }, "non-reversed" => sub { my %hash; my $data = $data; $hash{$1} = $2 while $data =~ s/\s*(\w+)\s*=\s*([^=]+)$//; }, }); __DATA__ option1 = value0 value1 value2 option3 =value3 value4 option2=value5