gistfile1.rb

require 'benchmark'

N = 1_000_000

a = []

100.times { a << (rand(10) > 5 ? true : false) }

Benchmark.bm(20) { |x|
 x.report("String#to_i(base)") {
   N.times { a.map {|v| v ? "1" : "0" }.join().to_i(2) }
 }

 x.report("Bit shift") {
   N.times { tmp = 0; a.each {|v| tmp |= (v ? 1 : 0); tmp <<= 1}; tmp >>= 1  }
 }
}

=begin

roelofs@trillian ~/tmp $ ruby test.rb
                          user     system      total        real
String#to_i(base)    51.880000   0.130000  52.010000 ( 54.645228)
Bit shift           151.350000   0.400000 151.750000 (159.552085)

=end