set集合,在Python中的书写方式的{},集合与之前列表、元组类似,可以存储多个数据,但是这些数据是不重复的
集合对象还支持union(联合), intersection(交), difference(差)和sysmmetric_difference(对称差集)等数学运算.
In [4]: a = [11,22,33,33,44,22,55]
In [5]: set(a)
Out[5]: {11, 22, 33, 44, 55}
In [7]: a = {11,22,33,44,55}
In [8]: b = {22,44,55,66,77}
In [9]: a&b
Out[9]: {22, 44, 55}
In [11]: a = {11,22,33,44,55}
In [12]: b = {22,44,55,66,77}
In [13]: a | b
Out[13]: {11, 22, 33, 44, 55, 66, 77}
In [15]: a = {11,22,33,44,55}
In [16]: b = {22,44,55,66,77}
In [17]: b - a
Out[17]: {66, 77}
In [19]: a = {11,22,33,44,55}
In [20]: b = {22,44,55,66,77}
In [21]: a ^ b
Out[21]: {11, 33, 66, 77}