python学习-字典的增删改查

1 dic1 = {‘name‘:‘paoche‘,
2         ‘age‘:19,
3         ‘active‘:[‘beijing‘,‘hebei‘],
4         ‘id‘:{‘wangyi‘:‘skmdod008b‘,
5               ‘sina‘:‘skmdod00bc‘
6               }
7         }

1 dic1[‘high‘] = 180      #没有键值对，则追加
2 dic1[‘age‘] = 30        #有键值，则修改
3 print(dic1)
4 """
5 结果为：
6 {‘name‘: ‘paoche‘, ‘age‘: 19, ‘active‘: [‘beijing‘, ‘hebei‘], ‘id‘: {‘wangyi‘: ‘skmdod008b‘, ‘sina‘: ‘skmdod00bc‘}}
7 {‘name‘: ‘paoche‘, ‘age‘: 30, ‘active‘: [‘beijing‘, ‘hebei‘], ‘id‘: {‘wangyi‘: ‘skmdod008b‘, ‘sina‘: ‘skmdod00bc‘}, ‘high‘: 180}
8 """

1 dic1.setdefault(‘weight‘,185)           #没有键值对，则追加
2 dic1.setdefault(‘name‘,‘xiaobai‘)       #有键值，则不做任何操作
3 print(dic1)
4 """
5 结果为：
6 {‘name‘: ‘paoche‘, ‘age‘: 19, ‘active‘: [‘beijing‘, ‘hebei‘], ‘id‘: {‘wangyi‘: ‘skmdod008b‘, ‘sina‘: ‘skmdod00bc‘}, ‘weight‘: 185}
7 """

1 print(dic1.pop(‘id‘))           #按键删除，返回被删除的键值对中的值，没有对应的键则报错
2 print(dic1.pop(‘id‘,None))      #按键删除，若没有该键，则返回指定的值，一般返回None，也可以是任意内容
3 print(dic1)
4 """
5 结果为：
6 {‘wangyi‘: ‘skmdod008b‘, ‘sina‘: ‘skmdod00bc‘}
7 None
8 {‘name‘: ‘paoche‘, ‘age‘: 19, ‘active‘: [‘beijing‘, ‘hebei‘]}
9 """

1 print(dic1.popitem())       #随机删除，返回被删键值组成的元组
2 """
3 结果为：
4 (‘id‘, {‘wangyi‘: ‘skmdod008b‘, ‘sina‘: ‘skmdod00bc‘})
5 """

1 print(dic1.clear())     #返回None
2 print(dic1)
3 """
4 结果为：
5 None
6 {}
7 """

1 del dic1[‘id‘]
2 print(dic1)
3 del dic1
4 """
5 结果为：
6 {‘name‘: ‘paoche‘, ‘age‘: 19, ‘active‘: [‘beijing‘, ‘hebei‘]}
7 """

1 dic1[‘age‘] = 30

 1 dic2 = {
 2     ‘name‘:‘paoche‘,
 3     ‘age‘:19
 4 }
 5 dic3 = {
 6     ‘age‘:30,
 7     ‘weight‘:180
 8 }
 9 dic2.update(dic3)    #将dic3中的数据更新dic2，有则修改，没有则新加
10 print(dic2)
11 """
12 结果为：
13 {‘name‘: ‘paoche‘, ‘age‘: 30, ‘weight‘: 180}
14 """

1 print(dic1[‘age‘])
2 ‘‘‘
3 结果为：
4 19
5 ‘‘‘

1 print(dic1.get(‘age‘))
2 print(dic1.get(‘age1‘))
3 print(dic1.get(‘age1‘,‘没有对应的键‘))
4 ‘‘‘
5 结果为：
6 19
7 None
8 没有对应的键
9 ‘‘‘

1 print(dic1.keys())
2 ‘‘‘
3 结果为：
4 dict_keys([‘name‘, ‘age‘, ‘active‘, ‘id‘])
5 ‘‘‘

1 print(dic1.values())
2 ‘‘‘
3 结果为：
4 dict_values([‘paoche‘, 19, [‘beijing‘, ‘hebei‘], {‘wangyi‘: ‘skmdod008b‘, ‘sina‘: ‘skmdod00bc‘}])
5 ‘‘‘

1 print(dic1.items())
2 ‘‘‘
3 结果为：
4 dict_items([(‘name‘, ‘paoche‘), (‘age‘, 19), (‘active‘, [‘beijing‘, ‘hebei‘]), (‘id‘, {‘wangyi‘: ‘skmdod008b‘, ‘sina‘: ‘skmdod00bc‘})])
5 ‘‘‘

1 for k,v in dic1.items():
2     print(k,v)
3 ‘‘‘
4 结果为：
5 name paoche
6 age 19
7 active [‘beijing‘, ‘hebei‘]
8 id {‘wangyi‘: ‘skmdod008b‘, ‘sina‘: ‘skmdod00bc‘}
9 ‘‘‘