红宝石 |设置 compare_by_identity()函数

compare_by_identity()是 Ruby 中的一个内置方法，它使集合通过其身份比较其元素并返回 self。 Set 的所有子类可能不支持此方法。

Syntax: s1.name.compare_by_identity()

Parameters: The function does not takes any parameter.

Return Value: It returns self after comparing its elements.

示例 1 ：

#Ruby program to illustrate the compare_by_identity() method
  
#requires the set
require "set"
  
    s1
    = Set[]
  
#Add 10 to it
      s1
      << 10
  
#Returns self after comparing internally
         puts s1.compare_by_identity()
  
             s1
      << 'a'
  
#Returns self after comparing internally
         puts s1.compare_by_identity()

输出：

Set: {10}
Set: {10, "a"}

示例 2 ：

#Ruby program to illustrate the clear method
  
#requires the set
require "set"
  
    s1
    = Set[]
  
#Prints s1
      puts s1
  
#Add 10 to it
          s1
      << 10
  
         puts s1
  
#Clears the set and returns self
#which is printed
             puts s1.clear

输出：

Set: {}
Set: {10}
Set: {}

参考：https://devdocs.io/ruby~2.5/set#method-i-compare_by_identity