无序，元素唯一, 一般用于元素去重
定义一个集合
set1 = set()
print(set1)
print(type(set1))
set()
<class 'set'>
set1 = {1, 2, 3, 5, 4}
print(type(set1))
<class 'set'>
添删改查
添加
set.add( )
set1.add(8)
print(set1)
{1, 2, 3, 4, 5, 8}
删除
不存在会报错
set.remove()
set.pop() 随机删除集合中的元素(由于集合的无序性)
set.discard() 如果存在就直接删除，不存在就不进行任何操作
set1 = {1, 2, 3, 5, 4}
set1.remove(1)
print(set1)
{2, 3, 4, 5}
set1 = {1, 2, 3, 5, 4}
set1.remove(10)
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
<ipython-input-1-8be039e36d7a> in <module>
1 set1 = {1, 2, 3, 5, 4}
----> 2 set1.remove(10)
KeyError: 10
set1 = {1, 2, 3, 5, 4}
set1.pop()
print(set1)
{2, 3, 4, 5}
set1 = {1, 2, 3, 5, 4}
set1.discard(10)
print(set1)
{1, 2, 3, 4, 5}
集合解析
from random import randint
set1 = {randint(0, 20) for _ in range(20)}
print (set1)
{0, 2, 5, 6, 8, 9, 11, 12, 13, 14, 15, 16, 19}
找到能能被三整除的
res = {x for x in set1 if x%3 == 0}
print(res)
{0, 6, 9, 12, 15}
