[ruby] 一覧から重複削除してnilを除去、の実装方法別パフォーマンス比較

bench_uniq_reject.rb

require 'benchmark/ips'
require 'benchmark/memory'

require 'set'

CLASSES = [
  Class.new {
    @arr = ['1', '2', '33', '444', nil, '5555', nil, '444', '66666', 'abcde', '777777', nil, 'XXXX', '33', 'zzzzzzzzzz']

    def self.label
      'Set->reject'
    end

    def self.exec
      Set.new(@arr).reject{|a| a.nil? }
    end
  },
  Class.new {
    @arr = ['1', '2', '33', '444', nil, '5555', nil, '444', '66666', 'abcde', '777777', nil, 'XXXX', '33', 'zzzzzzzzzz']

    def self.label
      'Set->reject!'
    end

    def self.exec
      Set.new(@arr).reject!{|a| a.nil? }
    end
  },
  Class.new {
    @arr = ['1', '2', '33', '444', nil, '5555', nil, '444', '66666', 'abcde', '777777', nil, 'XXXX', '33', 'zzzzzzzzzz']

    def self.label
      'uniq->reject'
    end

    def self.exec
      @arr.uniq.reject{|a| a.nil? }
    end
  },
  Class.new {
    @arr = ['1', '2', '33', '444', nil, '5555', nil, '444', '66666', 'abcde', '777777', nil, 'XXXX', '33', 'zzzzzzzzzz']

    def self.label
      'uniq->reject!'
    end

    def self.exec
      @arr.uniq.reject!{|a| a.nil? }
    end
  },
]

def ips
  Benchmark.ips do |x|
    x.time = 15
    x.warmup = 5

    CLASSES.each do |c|
      x.report(c.label) { c.exec }
    end

    x.compare!
  end
end

def memory
  Benchmark.memory do |x|
    CLASSES.each do |c|
      x.report(c.label) { c.exec }
    end

    x.compare!
  end
end

ips
memory

.reject{|a| a.nil? } の代わりに compact を、.reject!{|a| a.nil? } の代わりに compact! を使った場合も比較対象に追加して計測

→ compact!, compact が速い

% ruby bench_uniq_reject.rb

Warming up --------------------------------------
     Set->reject nil    12.032k i/100ms
    Set->reject! nil    11.094k i/100ms
    uniq->reject nil    20.897k i/100ms
   uniq->reject! nil    21.951k i/100ms
       uniq->compact    24.669k i/100ms
      uniq->compact!    25.309k i/100ms
Calculating -------------------------------------
     Set->reject nil    115.901k (± 7.7%) i/s -      1.733M in  15.047491s
    Set->reject! nil    107.887k (± 8.4%) i/s -      1.609M in  15.034735s
    uniq->reject nil    220.234k (± 4.3%) i/s -      3.302M in  15.024091s
   uniq->reject! nil    234.395k (± 3.5%) i/s -      3.512M in  15.003571s
       uniq->compact    261.002k (± 3.8%) i/s -      3.922M in  15.052946s
      uniq->compact!    276.562k (± 3.4%) i/s -      4.151M in  15.027452s

Comparison:
      uniq->compact!:   276561.9 i/s
       uniq->compact:   261001.6 i/s - same-ish: difference falls within error
   uniq->reject! nil:   234394.6 i/s - 1.18x  slower
    uniq->reject nil:   220234.3 i/s - 1.26x  slower
     Set->reject nil:   115900.6 i/s - 2.39x  slower
    Set->reject! nil:   107886.9 i/s - 2.56x  slower

Calculating -------------------------------------
     Set->reject nil     1.952k memsize (     0.000  retained)
                        19.000  objects (     0.000  retained)
                        10.000  strings (     0.000  retained)
    Set->reject! nil     1.936k memsize (     0.000  retained)
                        21.000  objects (     0.000  retained)
                        10.000  strings (     0.000  retained)
    uniq->reject nil   728.000  memsize (     0.000  retained)
                        12.000  objects (     0.000  retained)
                        10.000  strings (     0.000  retained)
   uniq->reject! nil   528.000  memsize (     0.000  retained)
                        11.000  objects (     0.000  retained)
                        10.000  strings (     0.000  retained)
       uniq->compact   656.000  memsize (     0.000  retained)
                        12.000  objects (     0.000  retained)
                        10.000  strings (     0.000  retained)
      uniq->compact!   528.000  memsize (     0.000  retained)
                        11.000  objects (     0.000  retained)
                        10.000  strings (     0.000  retained)

Comparison:
   uniq->reject! nil:        528 allocated
      uniq->compact!:        528 allocated - same
       uniq->compact:        656 allocated - 1.24x more
    uniq->reject nil:        728 allocated - 1.38x more
    Set->reject! nil:       1936 allocated - 3.67x more
     Set->reject nil:       1952 allocated - 3.70x more