字典----增、删、改、查、遍历、排序

#增加字典值

方法一:

massage = {"name":wade,"age":30,"hobby":["girl","book","money"]}

massage["work"]="程序猿"

print(massage)

 

方法二:

dict1 = massage.setdefault("work","程序猿")

print(dict1)

#该方法拥有返回值!

#当增加的元素key值存在时,返回值为原始值

dict1 = massage.setdefault("name","james")

print(dict1)    #返回值为wade

 

#当增加的元素可以值不存在时,返回值为value

dict1 = massage.setdefault("city","XIAN")

print(dict1)    #返回值为XIAN

 

#查

massage = {"name":wade,"age":30,"hobby":["girl","book","money"]}

dic1 = massage["name"]          #通过键查找

 

dic2 = massage.keys()            #查看所有的键,该方法返回的是一个列表键类型的数据,如需使用必须转换成list类型

print(list(massage.keys()))

 

dic3 = massage.values()        #查看所有的值

print(dic3)

 

dic4 = massage.items()          #查看所有的键值对,结果以列表形式返回,列表内的键值对以元祖形式存储

print(dic4)

 

#改 

massage = {"name":wade,"age":30,"hobby":["girl","book","money"]}

massage["name"] = "James"

 

massage2 = {"address":"XIAN","work":"IT","age":29}

massage.update(massage2)              #将massage2中数据加入到massage中,若有重复数据,则覆盖massage中的数据

print(massage)

 

#删

massage = {"name":wade,"age":30,"hobby":["girl","book","money"]}

del massage                          #删除字典

del(massage["name"])             #删除指定的键值对

massage.clear()                    #清空列表

massage.pop("name")           #有返回值,返回值为成功删除的值

massage.popitem()                #随机删除一组键值对

 

#排序           按照键的数序(ASCII码)排列

dic = {5:"555",2:"666",4:"44"}

print(sorted(dic))

 

for循环遍历

dic1 = {"name":"wade","age":18,"address":"xian"}

for i in dic1

  print(i,dic1[i])

 

获取字典的所有key

dic = {5:"555",2:"666",4:"44"}

keys = dic.keys()

print(type(keys))             

注:此处获得的key并非列表,而是<class 'dict_keys'>类型,如需获取其中值必须使用list()方法强转          

 

字典排序(多用于加密处理)

import  operator

test_dict = {'a':5, 'b':3, 'c':1}

# key=operate.itemgetter(0)     参数 0: key排序,1: value排序

res = sorted(test_dict.items(), key=operator.itemgetter(0)) 

posted @   Chaman囍  阅读(177)  评论(0编辑  收藏  举报
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