WHEN有可能檢查變量是否屬於數組？

Question

我該如何做這樣的事情？還是我需要一直使用IF？

ar = [["a","b"],["c"],["d","e"]] 
x = "b" 
case x 
when ar[0].include?(x) 
    puts "do something" 
when ar[1].include?(x) 
    puts "do else" 
when ar[2].include?(x) 
    puts "do a 3rd thing" 
end 

我使用Ruby 1.8.7

Answer 1

這不僅是可能的，這很容易。對於恆數組：

#!/usr/bin/ruby1.8 

x = "a" 
case x 
when 'a', 'b' 
    puts "do something" # => do something 
when 'c' 
    puts "do else" 
when 'd', 'e' 
    puts "do a 3rd thing" 
end 

或者，如果數組是不是恆定的：

#!/usr/bin/ruby1.8 

ar = [["a","b"],["c"],["d","e"]] 
x = 'd' 
case x 
when *ar[0] 
    puts "do something" 
when *ar[1] 
    puts "do else" 
when *ar[2] 
    puts "do a 3rd thing" # => do a 3rd thing 
end 

Answer 2

你爲什麼不重組你的代碼了一下，做

ar = [["a","b"],["c"],["d","e"]] 
x = "b" 
i = (0...ar.length).find {|i| ar[i].include?(x)} 
case i 
    when 0 
     puts "do something" 
    when 1 
     puts "do else" 
    when 2 
     puts "do a 3rd thing" 
end