WHEN有可能检查变量是否属于数组？

Question

我该如何做这样的事情？还是我需要一直使用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

这不仅是可能的，这很容易。对于恒数组：

#!/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，如果数组是不是恒定的：

#!/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

你为什么不重组你的代码了一下，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