Ruby 集合 compare_by_identity()函数

compare_by_identity() 是Ruby中的一个内置方法，它使集合根据其元素的身份进行比较并返回self。并非所有的Set的子类都支持这个方法。

语法：s1.name.compare_by_identity()

参数：该函数不需要任何参数。

返回值 : 在比较其元素后，它将返回自己。

例子 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"}

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