Ruby Hash key()函数

Hash#key()是一个Hash类方法，它给出了与value对应的key值。如果值不存在，则返回nil。

语法。Hash.key()

参数：哈希值

返回：与该值对应的键

nil – 如果值不存在

例子 #1 :

# Ruby code for Hash.key() method
  
# declaring Hash value
a = {a:100, b:200}
  
# declaring Hash value
b = {a:100, c:300, b:200}
  
# declaring Hash value
c = {a:100}
  
  
# key Value
puts "Hash a key form : #{a.key(200)}\n\n"
  
puts "Hash b key form : #{b.key(100)}\n\n"
  
puts "Hash c key form : #{c.key(200)}\n\n"

输出:

Hash a key form : b

Hash b key form : a

Hash c key form : 

例子 #2 :

# Ruby code for Hash.key() method
  
# declaring Hash value
a = { "a" => 100, "b" => 200 }
  
# declaring Hash value
b = {"a" => 100}
  
# declaring Hash value
c = {"a" => 100, "c" => 300, "b" => 200}
  
# key Value
puts "Hash a key form : #{a.key(200)}\n\n"
  
puts "Hash b key form : #{b.key(100)}\n\n"
  
puts "Hash c key form : #{c.key(200)}\n\n"

输出:

Hash a key form : b

Hash b key form : a

Hash c key form : b