From: Joel VanderWerf <vjoel@...>
Date: 2009-07-21T04:24:56+09:00
Subject: Re: getting char from string as fixnum in 1.8 and 1.9

Joel VanderWerf wrote:
> David A. Black wrote:
>>   def third_char_as_fixnum(s)
>>     s[2,1].unpack("C*")[0]
>>   end

About a factor of three slower, as I measure it:

require 'benchmark'

if RUBY_VERSION =~ /\A1\.9/
   def third_char_as_fixnum_1(s)
     s[2].ord
   end
else
   def third_char_as_fixnum_1(s)
     s[2]
   end
end

def third_char_as_fixnum_2(s)
   s[2,1].unpack("C").first
end

s = "abc"
N = 1_000_000

Benchmark.bmbm(12) do |bm|
   bm.report("1") {N.times {third_char_as_fixnum_1(s)}}
   bm.report("2") {N.times {third_char_as_fixnum_2(s)}}
end

__END__

Rehearsal -----------------------------------------------
1             1.060000   0.000000   1.060000 (  1.079800)
2             1.620000   0.000000   1.620000 (  1.634525)
-------------------------------------- total: 2.680000sec

                   user     system      total        real
1             0.580000   0.000000   0.580000 (  0.598929)
2             1.640000   0.000000   1.640000 (  1.664318)

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407