當案件包括在陣列

Question

這甚至可能與switch case？我看了帖子here，但它不適應。

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條款可以接受多個值：

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

Answer 2

你可以提供一個進程的case語句：

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

這工作，因爲紅寶石使用===運營商確定的平等case語句，並且Proc#===使用比較值作爲參數來執行proc。所以：

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

...雖然我很喜歡@查克的摔跤運營商爲這種特殊情況。

Answer 3

此選項值得一提：

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