group_vs_push.rb

require 'benchmark/ips'
 
def group
  (0..99).group_by { |i| i % 2 }
end
 
def push
  even = []
  odd = []
 
  (0..99).each do |i|
    if i % 2 == 0
      even << i
    else
      odd << i
    end
  end
end
 
def partition
  even, odd = (0..99).partition { |i| i % 2 == 0 }
end

def select
  (0..99).select { |i| i % 2 != 0 }
end
 
def single_push
  even = []
  (0..99).each do |i|
    if i % 2 == 0
      even << i
    end
  end
end

Benchmark.ips do |x|
  x.report("group")       { |times| times.times do group; end }
  x.report("push")        { |times| times.times do push; end }
  x.report("partition")   { |times| times.times do partition; end }
  x.report("select")      { |times| times.times do select; end }
  x.report("single push") { |times| times.times do single_push; end }
  x.compare!
end

run_1

Calculating -------------------------------------
               group     4.576k i/100ms
                push     5.732k i/100ms
           partition     5.693k i/100ms
              select     6.382k i/100ms
         single push     7.414k i/100ms
-------------------------------------------------
               group     60.612k (±13.4%) i/s -    297.440k
                push     76.997k (±10.6%) i/s -    384.044k
           partition     73.989k (± 6.6%) i/s -    370.045k
              select     80.999k (± 6.1%) i/s -    408.448k
         single push    102.651k (± 6.6%) i/s -    511.566k

Comparison:
         single push:   102650.5 i/s
              select:    80999.4 i/s - 1.27x slower
                push:    76996.7 i/s - 1.33x slower
           partition:    73989.1 i/s - 1.39x slower
               group:    60611.6 i/s - 1.69x slower

run_2

Calculating -------------------------------------
               group     4.576k i/100ms
                push     5.732k i/100ms
           partition     5.693k i/100ms
              select     6.382k i/100ms
         single push     7.414k i/100ms
-------------------------------------------------
               group     60.612k (±13.4%) i/s -    297.440k
                push     76.997k (±10.6%) i/s -    384.044k
           partition     73.989k (± 6.6%) i/s -    370.045k
              select     80.999k (± 6.1%) i/s -    408.448k
         single push    102.651k (± 6.6%) i/s -    511.566k

Comparison:
         single push:   102650.5 i/s
              select:    80999.4 i/s - 1.27x slower
                push:    76996.7 i/s - 1.33x slower
           partition:    73989.1 i/s - 1.39x slower
               group:    60611.6 i/s - 1.69x slower