红宝石 |哈希键（）函数

Hash#keys()是一个 Hash 类方法，它提供一个包含哈希中存在的所有键的数组。

Syntax: Hash.keys()

Parameter: Hash values

Return: array with all the keys present in the hash

示例 #1：

# Ruby code for Hash.keys() 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}
  
  
# keys Value
puts "Hash a keys form : #{a.keys()}\n\n"
  
puts "Hash b keys form : #{b.keys()}\n\n"
  
puts "Hash c keys form : #{c.keys()}\n\n"

输出 ：

Hash a keys form : [:a, :b]

Hash b keys form : [:a, :c, :b]

Hash c keys form : [:a]

示例 #2：

# Ruby code for Hash.keys() 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}
  
  
# keys Value
puts "Hash a keys form : #{a.keys()}\n\n"
  
puts "Hash b keys form : #{b.keys()}\n\n"
  
puts "Hash c keys form : #{c.keys()}\n\n"

输出 ：

Hash a keys form : ["a", "b"]

Hash b keys form : ["a"]

Hash c keys form : ["a", "c", "b"]