1.集合
In [1]: a = (11,22,33,11,22,33)
In [2]: a
Out[2]: (11, 22, 33, 11, 22, 33) #元组
In [3]: b = [11,22,33,11,22,33]
In [4]: b #列表
Out[4]: [11, 22, 33, 11, 22, 33]
In [5]: c = {11,22,33,11,22,33} #集合
In [6]: c
Out[6]: {11, 22, 33}
##### 集合 去重
In [9]: type(c)
Out[9]: set
2.set集合操作
In [12]: s
Out[12]: {11, 22, 33}
In [13]: s.
s.add s.intersection s.remove
s.clear s.intersection_update s.symmetric_difference
s.copy s.isdisjoint s.symmetric_difference_update
s.difference s.issubset s.union
s.difference_update s.issuperset s.update
s.discard s.pop
#### 增删改查
s.add
s.pop
s.remove
s.update
### 查看帮助文档
In [13]: help(s.add)
Help on built-in function add:
add(...) method of builtins.set instance
Add an element to a set.
This has no effect if the element is already present.
(END)
#### 增add
In [15]: s.add(55)
In [16]: s
Out[16]: {11, 22, 33, 55}
In [17]: s.add(55)
In [18]: s
Out[18]: {11, 22, 33, 55}
3.面试题:list列表去重
1) 版本1
a = [11,22,33,11,22,33]
print(a)
b = []
for i in a:
if i not in b:
b.append(i)
print(b)
###3 运行结果
[11, 22, 33, 11, 22, 33]
[11, 22, 33]
2)版本2:set去重
In [1]: a = [11,22,33,11,22,33]
In [4]: s = set(a) #list列表类型转换为set集合类型
In [5]: s
Out[5]: {11, 22, 33} #去重
In [6]: a = list(s) #再转换为list列表
In [7]: a
Out[7]: [33, 11, 22]