删除Ruby Array中的重复项

我可以通过使用很容易地删除数组中的重复项.uniq,但是如何在不使用该.uniq方法的情况下执行此操作？

a = [1, 1, 1, 2, 4, 3, 4, 3, 2, 5, 5, 6]

class Array
  def my_uniq
    self | []
  end
end

a.my_uniq
  #=> [1, 2, 4, 3, 5, 6]

这使用方法Array#| :"Set Union - 通过将ary与other_ary连接,返回一个新数组,排除任何重复项并保留原始数组中的顺序."

这是各种答案的基准,以及Array#uniq.

require 'fruity'
require 'set'

def doit(n, m)
  arr = n.times.to_a
  arr = m.times.map { arr.sample }
  compare do
    uniq     { arr.uniq } 
    Schwern  { uniq = []; arr.sort.each { |e| uniq.push(e) if e != uniq[-1]; uniq } }
    Sharma   {b = []; arr.each{ |aa| b << aa unless b.include?(aa) }; b }
    Mihael   { arr.to_set.to_a }
    sawa     { arr.group_by(&:itself).keys }
    Cary     { arr | [] }
  end
end

doit(1_000, 500)
# Schwern is faster than uniq by 19.999999999999996% ± 10.0% (results differ)
# uniq is similar to Cary
# Cary is faster than Mihael by 10.000000000000009% ± 10.0%
# Mihael is similar to sawa
# sawa is faster than Sharma by 5x ± 0.1

doit(100_000, 50_000)
# Schwern is faster than uniq by 50.0% ± 10.0%               (results differ)
# uniq is similar to Cary
# Cary is similar to Mihael
# Mihael is faster than sawa by 10.000000000000009% ± 10.0%
# sawa is faster than Sharma by 310x ± 10.0

"Schwern"和"uniq"返回包含相同元素但不以相同顺序排列的数组(因此"结果不同").

这是@Schern要求的额外基准.

def doit1(n)
  arr = n.times.map { rand(n/10) }
  compare do
    uniq     { arr.uniq } 
    Schwern  { uniq = []; arr.sort.each { |e| uniq.push(e) if e != uniq[-1]; uniq } }
    Sharma   {b = []; arr.each{ |aa| b << aa unless b.include?(aa) }; b }
    Mihael   { arr.to_set.to_a }
    sawa     { arr.group_by(&:itself).keys }
    Cary     { arr | [] }
  end
end

doit1(1_000)
# Cary is similar to uniq
# uniq is faster than sawa by 3x ± 1.0
# sawa is similar to Schwern                     (results differ)
# Schwern is similar to Mihael                   (results differ)
# Mihael is faster than Sharma by 2x ± 0.1

doit1(50_000)
# Cary is similar to uniq
# uniq is faster than Schwern by 2x ± 1.0        (results differ)
# Schwern is similar to Mihael                   (results differ)
# Mihael is similar to sawa
# sawa is faster than Sharma by 62x ± 10.0