gistfile1.rb

require 'benchmark'

N = 100_000

a = []

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

Benchmark.bm(35) { |x|
 x.report("String#to_i(base)") {
   N.times { a.map {|v| v ? "1" : "0" }.join().to_i(2) }
 }

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

 x.report("Bit shift") {
   N.times { a.inject(0) {|m, v| m <<= 1; m | (v ? 1 : 0) } }
 }

 # Precompute
 a.map! {|v| v ? "1" : "0" }
 x.report("String#to_i(premapped)") {
   N.times { a.join().to_i(2) }
 }

 a.map! {|v| v.to_i }
 x.report("Bit shift(premapped)") {
   N.times { a.inject(0) {|m, v| m <<= 1; m | v } }
 }
}

=begin

gaffneyc@magrathea ~/dev/git/47994 (master) $ ruby gistfile1.rb
                                         user     system      total        real
String#to_i(base)                    4.950000   0.020000   4.970000 (  5.004080)
String#to_i(base integers)          10.400000   0.050000  10.450000 ( 10.557950)
Bit shift                           20.770000   0.090000  20.860000 ( 21.046028)
String#to_i(premapped)               1.040000   0.010000   1.050000 (  1.064023)
Bit shift(premapped)                20.140000   0.090000  20.230000 ( 20.413547)

=end