require "benchmark/ips"

A_SIZE_RANGE = 0..1000
B_SIZE_RANGE = 2..5
VAL_RANGE = 0...10000

def a
  Array.new(rand A_SIZE_RANGE) { rand VAL_RANGE }
end

def b
  Array.new(rand B_SIZE_RANGE) { rand VAL_RANGE }
end

Benchmark.ips do |x|
  x.report("(a&b).any?") { (a & b).any? }
  x.report("a.any? {|item| b.include?(item) }") { a.any? {|item| b.include?(item) } }
  x.compare!
end