增：
add
a = {1,2,3}
a.add(4)
print(a)
#{1, 2, 3, 4}
删：
discard、remove、pop
a = {1,2,3}
a.remove(1)
print(a)
a.discard(1)
print(a)
a.discard(2)
print(a)
#{2, 3}
#{2, 3}
#{3}
改(不支持，也不支持切片，无索引)：
a = {1,2,3}
print(a[0])
# File "E:/pythondir/Day01/task02.py", line 2, in <module>
print(a[0])
TypeError: ‘set‘ object is not subscriptable
查：
in or not in
并集：
| 、union
a = {1,2,3,4,5}
b = {2,3,5,6,7,8,9}
print(a | b)
print(a.union(b))
#{1, 2, 3, 4, 5, 6, 7, 8, 9}
#{1, 2, 3, 4, 5, 6, 7, 8, 9}
差集：
-、difference
a = {1,2,3,4,5}
b = {2,3,5,6,7,8,9}
print(a - b)
print(a.difference(b))
print(a.difference_update(b)) #去掉交集,并更新
print(a)
#{1, 4}
#{1, 4}
#None
#{1, 4}
交集：
&、intersection
a = {1,2,3,4,5}
b = {2,3,5,6,7,8,9}
print(a & b)
print(a.intersection(b))
#{2, 3, 5}
#{2, 3, 5}
对称差集（两者并集去掉交集）：
^、symmetric_difference
a = {1,2,3,4,5}
b = {2,3,5,6,7,8,9}
print(a ^ b)
print(a.symmetric_difference(b))
#{1, 4, 6, 7, 8, 9}
#{1, 4, 6, 7, 8, 9}
原文：https://www.cnblogs.com/thanos-ryan/p/13258136.html