WHEN是否可以检查变量是否属于数组? [英] Is it possible for WHEN to check the if the variable belongs to an array?

问题描述

我该怎么做?还是我需要一直使用IF?

How can I do something like this ? or do i need to use IF all the time?

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

我正在使用ruby 1.8.7

I'm using ruby 1.8.7

推荐答案

不仅可行，而且很容易.对于常量数组:

It's not only possible, it's easy. For constant arrays:

#!/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，如果数组不是恒定的:

Or, if the arrays aren't constant:

#!/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

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