版权声明:版权所有,翻版必究【Kevin】 https://blog.csdn.net/weixin_30935137/article/details/82890801
字典{}定义
字典是另一种可变容器模型,且可存储任意类型对象。
字典的每个键值(key : value)对用冒号(:)分割,每个对之间用逗号(,)分割,整个字典包括在花括号({})中
键必须是唯一的,值不必须。
key必须是不可变对象,value则可以是任意对象(数值/字符串/序列/字典)
声明字典
dic1 = {'a':1,'b':2}
list1 = [('a',1),('b',2)]
list2 = [('a','wujiadong'),('b','zhangdandan')]
list3 = [('a',[1,2]),('b',[3,4])]
dic2 = dict(list1)
dic3 = dict(list2)
dic4 = dict(list3)
print(dic2)
print(dic3)
print(dic4)
结果如下:
{'a': 1, 'b': 2}
{'a': 'wujiadong', 'b': 'zhangdandan'}
{'a': [1, 2], 'b': [3, 4]}
字典常用操作
1)修改元素
info = {'name':'wujiadong','age':27,'address':"shanghai"}
print(info)
print('######################################################')
info['name'] = 'dandan'
info['address'] = 'jilin'
print(info)
结果如下:
{'name': 'wujiadong', 'age': 27, 'address': 'shanghai'}
######################################################
{'name': 'dandan', 'age': 27, 'address': 'jilin'}
2)添加元素
info['gender'] = 'female'
print(info)
{'name': 'dandan', 'age': 27, 'address': 'jilin', 'gender': 'female'}
3)删除元素
del info['gender']
print('删除后%s'%info)
print('#################################################')
info.clear()
print('清除后%s'%info)
结果如下:
删除后{'name': 'dandan', 'age': 27, 'address': 'jilin'}
#################################################
清除后{}
4)len()
info = {'name':'wujiadong','age':27,'address':"shanghai"}
print(len(info))
结果如下
3
5)keys()
info = {'name':'wujiadong','age':27,'address':"shanghai"}
keys= info.keys()
print(keys,type(keys))
for i in keys:
print(i)
结果如下:
dict_keys(['name', 'age', 'address']) <class 'dict_keys'>
name
age
address
6)values()
dict_keys(['name', 'age', 'address']) <class 'dict_keys'>
name
age
address
结果如下:
dict_values(['wujiadong', 27, 'shanghai']) <class 'dict_values'>
wujiadong
27
shanghai
7)items
info = {'name':'wujiadong','age':27,'address':"shanghai"}
items = info.items()
print(items,type(items))
结果如下:
dict_items([('name', 'wujiadong'), ('age', 27), ('address', 'shanghai')]) <class 'dict_items'>