ruby bsearch vs index

bsearch.rb

require 'benchmark'



a = (1..1000).to_a
lookup = 100000.times.map{(rand*1000).to_i}

puts "for index"
puts Benchmark.measure {
  lookup.each{ |i| a.index(i) }
}

puts "for bsearch"
puts Benchmark.measure {
  lookup.each{ |i| a.bsearch{|v| v >= i} }
}

result

 $ ruby bsearch.rb                                                                                                                                                         
for index                                                                                                                                                                  
  6.080000   0.010000   6.090000 (  6.084225)                                                                                                                              
for bsearch                                                                                                                                                                
  0.220000   0.000000   0.220000 (  0.218332)