Quick benchmark for .reject with rejected array initialization in loop and out of loop

benchmark.rb

require "benchmark"

ITEMS = { :foo => "bar", :fizz => "buzz", :fazz => "bazz" }
REJECTED_ITEMS = [:foo, :fazz]

# Number of iterations
@n = 10

def with_constant
  @n.times do
    ITEMS.reject{|k,v| REJECTED_ITEMS.include?(k) }
  end
end

def without_constant
  @n.times do
    ITEMS.reject{|k,v| [:foo, :fazz].include?(k) }
  end
end

Benchmark.bmbm do |x|
  x.report { with_constant }
  x.report { without_constant }
end

result_1

# Test run for n=10
╭─jason@jasons-mbp  ~  ‹master›
╰─$ ruby benchmark.rb
Rehearsal ------------------------------------
   0.000000   0.000000   0.000000 (  0.000031)
   0.000000   0.000000   0.000000 (  0.000025)
--------------------------- total: 0.000000sec

       user     system      total        real
   0.000000   0.000000   0.000000 (  0.000024)
   0.000000   0.000000   0.000000 (  0.000024)

result_2

# Test run for n=1000000
╭─jason@jasons-mbp  ~  ‹master›
╰─$ ruby benchmark.rb
Rehearsal ------------------------------------
   1.760000   0.030000   1.790000 (  1.790961)
   1.970000   0.020000   1.990000 (  1.987612)
--------------------------- total: 3.780000sec

       user     system      total        real
   1.720000   0.030000   1.750000 (  1.753787)
   1.970000   0.010000   1.980000 (  1.986179)