injectが遅いんですが何のためにあるとですか?
>> RUBY_DESCRIPTION
=> "ruby 1.8.7 (2008-08-11 patchlevel 72) [universal-darwin10.0]"
>> Benchmark.realtime{Array.new(1_000_000).inject(0){|r,|r+0}}
=> 1.62985396385193
>> Benchmark.realtime{sum=0; 1_000_000.times{sum+=0}}
=> 0.377360105514526