Python-基础知识-字典dict和集合set

>>> stu = {‘Michael‘: 95, ‘Bob‘: 75, ‘Tracy‘: 85}    #创建字典
>>> stu[‘Michael‘]
95

>>> info = {
...     ‘stu1101‘: "TengLan Wu",
...     ‘stu1102‘: "LongZe Luola",
...     ‘stu1103‘: "XiaoZe Maliya",
... }    #创建一个字典info
>>>
>>> info
{‘stu1103‘: ‘XiaoZe Maliya‘, ‘stu1101‘: ‘TengLan Wu‘, ‘stu1102‘: ‘LongZe Luola‘}
>>> info["stu1104"] = "苍井空"    #增加一个，如果没有这个键就增加，否则就修改这个键
>>> info
{‘stu1104‘: ‘苍井空‘, ‘stu1103‘: ‘XiaoZe Maliya‘, ‘stu1101‘: ‘TengLan Wu‘, ‘stu1102‘: ‘LongZe Luola‘}

>>> info.pop("stu1101")    #字典的内置方法，删除键名为stu1101
‘TengLan Wu‘
>>> info
{‘stu1104‘: ‘苍井空‘, ‘stu1103‘: ‘XiaoZe Maliya‘, ‘stu1102‘: ‘LongZe Luola‘}
>>> del info[‘stu1103‘]    #python自带的删除方法，删除键名为stu1103
>>> info
{‘stu1104‘: ‘苍井空‘, ‘stu1102‘: ‘LongZe Luola‘}
>>> info.popitem()    #随机删除一个
(‘stu1104‘, ‘苍井空‘)
>>> info
{‘stu1102‘: ‘LongZe Luola‘}

>>> ‘stu1102‘ in info     #判断成员关系
True
>>> info.get(‘stu1102‘)  #查找方法，如果查找对象不存在，此方法不报错，没有返回结果
‘LongZe Luola‘
>>> info[‘stu1105‘]    #此方法查找不存在的对象会报错
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: ‘stu1105‘

>>> info = {
...     ‘stu1101‘: "TengLan Wu",
...     ‘stu1102‘: "LongZe Luola",
...     ‘stu1103‘: "XiaoZe Maliya",
... }
>>>
>>>
>>> info.values()    #获取值
dict_values([‘XiaoZe Maliya‘, ‘TengLan Wu‘, ‘LongZe Luola‘])
>>> info.keys()    #获取键名
dict_keys([‘stu1103‘, ‘stu1101‘, ‘stu1102‘])
>>> info.items()    #获取键值对，以list的方式返回
dict_items([(‘stu1103‘, ‘XiaoZe Maliya‘), (‘stu1101‘, ‘TengLan Wu‘), (‘stu1102‘, ‘LongZe Luola‘)])

>>> info.setdefault("stu1106","Alex")
‘Alex‘
>>> info
{‘stu1102‘: ‘LongZe Luola‘, ‘stu1103‘: ‘XiaoZe Maliya‘, ‘stu1106‘: ‘Alex‘}
>>> info.setdefault("stu1102","龙泽萝拉")  #因为字典中已有stu1102，并且字典有自动去重功能
‘LongZe Luola‘
>>> info
{‘stu1102‘: ‘LongZe Luola‘, ‘stu1103‘: ‘XiaoZe Maliya‘, ‘stu1106‘: ‘Alex‘}

>>> info
{‘stu1102‘: ‘LongZe Luola‘, ‘stu1103‘: ‘XiaoZe Maliya‘, ‘stu1106‘: ‘Alex‘}
>>> b = {1:2,3:4, "stu1102":"龙泽萝拉"}
>>> info.update(b) #将字典b加入到字典info中
>>> info
{‘stu1102‘: ‘龙泽萝拉‘, 1: 2, 3: 4, ‘stu1103‘: ‘XiaoZe Maliya‘, ‘stu1106‘: ‘Alex‘}

#方法1，建议使用
for key in info:
    print(key,info[key])

#方法2
for k,v in info.items(): #会先把dict转成list，数据里大时莫用
    print(k,v)

>>> football = {
...     ‘英超‘:{
...         ‘曼联‘:{
...             ‘积分‘:60,
...             ‘进球‘:45,
...             ‘排名‘:1
...         },
...         ‘阿森纳‘:{
...             ‘积分‘:55,
...             ‘进球‘:30,
...             ‘排名‘:4
...         },
...         ‘切尔西‘:{
...             ‘积分‘:59,
...             ‘进球‘:40,
...             ‘排名‘:2
...         }
...     },
...     ‘中超‘:{
...         ‘广州恒大‘:{
...             ‘积分‘:45,
...             ‘进球‘:25,
...             ‘排名‘:1
...         },
...         ‘上海上港‘:{
...             ‘积分‘:20,
...             ‘进球‘:10,
...             ‘排名‘:2
...         },
...         ‘江苏苏宁‘:{
...             ‘积分‘:30,
...             ‘进球‘:40,
...             ‘排名‘:3
...         }
...     },
...     ‘西甲‘:{
...         ‘巴萨‘:{
...             ‘积分‘:60,
...             ‘进球‘:55,
...             ‘排名‘:1
...         },
...         ‘皇马‘:{
...             ‘积分‘:55,
...             ‘进球‘:59,
...             ‘排名‘:2
...         },
...         ‘马竞‘:{
...             ‘积分‘:55,
...             ‘进球‘:58,
...             ‘排名‘:3
...         }
...     }
... }
>>>
>>> football
{‘中超‘: {‘江苏苏宁‘: {‘排名‘: 3, ‘积分‘: 30, ‘进球‘: 40}, ‘广州恒大‘: {‘排名‘: 1, ‘积分‘: 45, ‘进球‘: 25}, ‘上海上港‘: {‘排名‘
: 2, ‘积分‘: 20, ‘进球‘: 10}}, ‘英超‘: {‘曼联‘: {‘排名‘: 1, ‘积分‘: 60, ‘进球‘: 45}, ‘阿森纳‘: {‘排名‘: 4, ‘积分‘: 55, ‘进球‘:
30}, ‘切尔西‘: {‘排名‘: 2, ‘积分‘: 59, ‘进球‘: 40}}, ‘西甲‘: {‘马竞‘: {‘排名‘: 3, ‘积分‘: 55, ‘进球‘: 58}, ‘巴萨‘: {‘排名‘: 1,
‘积分‘: 60, ‘进球‘: 55}, ‘皇马‘: {‘排名‘: 2, ‘积分‘: 55, ‘进球‘: 59}}}
>>> football[‘中超‘][‘广州恒大‘]
{‘排名‘: 1, ‘积分‘: 45, ‘进球‘: 25}
>>> football[‘中超‘][‘广州恒大‘][‘积分‘]
45

>>> set1 = set([1,3,4,5,99,54,22])
>>> set2 = set([3,22,5,6,7,10,4])
>>> set1
{1, 99, 3, 4, 5, 54, 22}
>>> set2
{3, 4, 5, 6, 7, 10, 22}
>>>
>>> set3 = set("Hello")    #创建一个唯一字符的集合
>>> set3
{‘e‘, ‘l‘, ‘H‘, ‘o‘}

>>> set1.add(20)
>>> set1
{1, 99, 3, 4, 5, 20, 54, 22}
>>> set2.update([10,37,42])
>>> set2
{3, 4, 5, 6, 7, 37, 10, 42, 22}

>>> set1.remove(1)    #如果元素不存在，会报错
>>> set1
{99, 3, 4, 5, 54, 22}
>>> set1.discard(100)    #如果元素存在就删除，不存在则do nothing
>>> set1
{99, 3, 4, 5, 54, 22}
>>> set1.pop()    #使用pop()随意删除一个
99
>>> set1
{3, 4, 5, 54, 22}
>>> len(set1)    #set 的长度
5

>>> set1 = set([1,3,4,5,99,54,22])
>>> set2 = set([3,22,5,6,7,10,4])
>>> set1
{1, 99, 3, 4, 5, 54, 22}
>>> set2
{3, 4, 5, 6, 7, 10, 22}
#包含set1和set2中的每一个元素，取并集（即A和B）
>>> set1.union(set2)
{1, 99, 3, 4, 5, 6, 7, 10, 54, 22}
>>> set3 = set1 | set2
>>> set3
{1, 99, 3, 4, 5, 6, 7, 10, 54, 22}
#包含set1和set2中相同的元素，取交集（即AB中都有的）
>>> set1.intersection(set2)
{3, 4, 5, 22}
>>> set3 = set1 & set2
>>> set3
{3, 4, 5, 22}
#包含set1中有但是set2中没有的元素，取差集（即A有B没有）
>>> set1.difference(set2)
{1, 99, 54}
>>> set3 = set1 - set2
>>> set3
{1, 99, 54}
#包含set1和set2中不重复的元素，取对称差集（即A有B没有，B有A没有）
>>> set1.symmetric_difference(set2)
{1, 6, 7, 99, 10, 54}
>>> set3 = set1 ^ set2
>>> set3
{1, 6, 7, 99, 10, 54}
#set4是否set5的子集
>>> set4 = set([1,2,3,4,5,6,7,8,9])
>>> set4
{1, 2, 3, 4, 5, 6, 7, 8, 9}
>>> set5 = set([1,3,5,7,9])
>>> set5
{1, 3, 5, 9, 7}
>>> set4.issubset(set5)
False
>>> set4
{1, 2, 3, 4, 5, 6, 7, 8, 9}
>>> set6 = set4 <= set5
>>> set6
False
#set4是否包含set5的全部元素
>>> set4.issuperset(set5)
True
>>> set4
{1, 2, 3, 4, 5, 6, 7, 8, 9}
>>> set6 = set4 >= set5
>>> set6
True

>>> set7 = set([1,2])
>>> set7
{1, 2}
>>> 1 in set7    #测试1是否是set7的成员
True
>>> set7 = set([1,2,100])
>>> set7
{1, 2, 100}
>>> 100 not in set7    #测试100是否不是set7的成员
False