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
输出:
Set: {}
Set: {10}
Set: {}
参考资料 : https://devdocs.io/ruby~2.5/set#method-i-compare_by_identity