Python 元组 集合

1. 元组

>>> a = (1,2,3,4,5)
>>> b = list(a) #转换成列表对象, 可以更改
>>> b
[1, 2, 3, 4, 5]
>>> b[0] = "HAHA" #更新列表内的值.
>>> b
[‘HAHA‘, 2, 3, 4, 5]
>>> c = tuple(b) #tuple,把列表转换成元组
>>> c
(‘HAHA‘, 2, 3, 4, 5)

2. 集合

>>> a = set(‘abc‘) #定义集合
>>> a
set([‘a‘, ‘c‘, ‘b‘])
>>> a.add(‘young‘) #增加成员
>>> a
set([‘a‘, ‘c‘, ‘b‘, ‘young‘])
>>> a.update(‘TEST‘) #更新成员
>>> a
set([‘a‘, ‘c‘, ‘b‘, ‘E‘, ‘young‘, ‘S‘, ‘T‘])
>>> a.remove(‘E‘)
>>> a
set([‘a‘, ‘c‘, ‘b‘, ‘young‘, ‘S‘, ‘T‘])
>>> a.update("TTTT") #没有重复
>>> a
set([‘a‘, ‘c‘, ‘b‘, ‘young‘, ‘S‘, ‘T‘])
>>> a.update("SB")
>>> a
set([‘a‘, ‘c‘, ‘b‘, ‘young‘, ‘S‘, ‘B‘, ‘T‘])
>>> a.remove(‘S‘) #移除成员
>>> a
set([‘a‘, ‘c‘, ‘b‘, ‘young‘, ‘B‘, ‘T‘])

>>> b = frozenset(‘abc‘)
>>> b
frozenset([‘a‘, ‘c‘, ‘b‘])
>>> b.add(‘a‘)
Traceback (most recent call last):
  File "<pyshell#17>", line 1, in <module>
    b.add(‘a‘)
AttributeError: ‘frozenset‘ object has no attribute ‘add‘

#成员关系
>>> a
set([‘a‘, ‘c‘, ‘b‘, ‘young‘, ‘B‘, ‘T‘])
>>> "a" in a
True
>>> "d" not in a
True

#集合交集,并集,差集
>>> a = set(‘abc‘)
>>> b = set(‘cde‘)
>>> a & b #交集
set([‘c‘])
>>> a | b #并集
set([‘a‘, ‘c‘, ‘b‘, ‘e‘, ‘d‘])
>>> a - b #差集
set([‘a‘, ‘b‘])

#列表去重复的值
>>> a = [1,2,3]
>>> a.append(2)
>>> a.append(3)
>>> a
[1, 2, 3, 2, 3]
>>> set(a) #转换成集合
set([1, 2, 3])
>>> list(set(a)) #转换成列表
[1, 2, 3]