arrays - 如何编写一个 ruby​​ 方法，该方法返回两个数组中相似但位置不同的项目的计数

Question

我正在尝试用 Ruby 编写游戏 Mastermind 的一个版本。为此，我需要编写一个方法，该方法将返回两个不同数组共有但位于不同位置的元素的数量。我已经有一个方法可以返回在同一索引处正确的项目数。

例如:

comparing ["red", "green", "red", "orange"] to ["blue", "red", "blue", "blue"]
#should return 1

comparing ["red", "red", "orange", "orange"] to ["orange", "orange", "red", "red"]
#should return 4

comparing ["green", "green", "orange", "blue"] to ["green", "green", "orange", "red"]
#should return 0

Answer 1

def f a, b
  c = [a, b].transpose.inject [] do |m, e|
    m << e if e.first != e.last
    m
  end.transpose
  puts c.first.size - (c.last - c.first).size
end

f [:red, :green, :red, :orange],    [:blue, :red, :blue, :blue]     # => 1
f [:red, :red, :orange, :orange],   [:orange, :orange, :red, :red]  # => 4
f [:green, :green, :orange, :blue], [:green, :green, :orange, :red] # => 0

# it works with Strings, also

f %w/red green red orange/,    %w/blue red blue blue/     # => 1
f %w/red red orange orange/,   %w/orange orange red red/  # => 4
f %w/green green orange blue/, %w/green green orange red/ # => 0