当大小写包含在案例中时

Question

switch case是否可以实现这一目标？我查看了帖子here，但它不具备适应性。

step = 'a'
arr = ['a', 'b', 'c']

case step
when arr.include?
  puts "var is included in array"
when "other"
  puts "nothing"
end

Answer 1

when子句可以接受多个值：

case step
when *arr
  puts "var is included in array"
when "other"
  puts "nothing"
end

Answer 2

这个选项值得一提：

step = 'a'
arr = ['a', 'b', 'c']
case
when arr.include?(step)
  puts "arr matches"
when arr2.include?(step)
  puts "arr2 matches"
end

Answer 3

您可以为案例陈述提供过程：

case step
when ->(x){ arr.include?(x) }
  puts "var is included"
when "other"
  puts "nothing"
end

这是有效的，因为ruby使用===运算符来确定case语句中的相等性，Proc#===使用比较值作为参数来执行proc。所以：

arr = [1,2,3]
proc = ->(x){ arr.include?(x) }
proc === 2 #=> true

...虽然我更喜欢这个特殊情况的@ Chuck的splat运算符。