小甲鱼《零基础学习Python》课后笔记（二十七）：集合——在我的世界里，你就是唯一

>>> set3 = {1,2,3,4,5,2,3,4,5,4}  
>>> set3  
{1, 2, 3, 4, 5}  

>>> set2 = frozenset([1,2,3,4,5])  
>>> set2.add(6)  
Traceback (most recent call last):  
	File "<pyshell#65>", line 1, in <module>  
	set2.add(6)  
AttributeError: 'frozenset' object has no attribute 'add'  

i = 0   
set1 = {1,2,3,4,5,6,7}  
for each in set1: 
	i++  
print(i)

>>> num_set = set([1,2,3,4,5])  
>>> num_set[0]  

>>> set1 = {1,1.0}  
>>> set1  
{1}  

>>> set4 ={1,2,3,4,6}  
>>> set4.add(5)  
>>> set4  
{1, 2, 3, 4, 5, 6}  
>>> set4.remove(6)  
>>> set4  
{1, 2, 3, 4, 5}