python开发基础：字典操作

  1 #!/usr/bin/env python
  2 #_*_coding:utf-8_*_
  3 
  4 
  5 # 常用操作：
  6 #
  7 # 　　　　存/取
  8 # info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
  9 # print(info_dic[‘name11111111‘]) #没有这个key,报错
 10 # print(info_dic.get(‘name1‘,None)) #最好用get取值,没有的情况下返回None，可以自己定义返回的这个None
 11 
 12 #pop：key存在则弹出值，不存在则返回默认值，如果没有默认值则报错
 13 # print(info_dic.pop(‘name‘,None))
 14 # print(info_dic)
 15 
 16 # print(info_dic.popitem()) #随机删除
 17 # print(info_dic)
 18 
 19 # info_dic[‘level‘]=10  #添加
 20 # print(info_dic)
 21 
 22 #
 23 # 　　　　删除
 24 # info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
 25 # info_dic.pop()
 26 # info_dic.popitem()
 27 # del info_dic[‘name‘]
 28 
 29 
 30 #
 31 # 　　　　键s，值s，键值对
 32 # info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
 33 # print(info_dic.keys())
 34 # print(info_dic.values())
 35 # print(info_dic.items())
 36 
 37 # for k in info_dic:
 38 #     # print(k,info_dic[k])
 39 #     print(k)
 40 
 41 # print(‘========>‘)
 42 # for k in info_dic.keys():
 43 #     print(k)
 44 
 45 # for val in info_dic.values():
 46 #     print(val)
 47 
 48 # for k,v in info_dic.items(): #k,v=(‘name‘, ‘egon‘)
 49 #     print(k,v)
 50 
 51 
 52 
 53 # 　　　　长度
 54 # info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
 55 # print(len(info_dic))
 56 #
 57 # 　　　　循环
 58 #
 59 # 　　　　包含in 默认比对的是KEY
 60 
 61 # info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
 62 # print(‘name‘ in info_dic)
 63 # print(‘name‘ in info_dic.keys())
 64 # print(‘egon‘ in info_dic.values())
 65 # print((‘name‘,‘egon‘) in info_dic.items())
 66 
 67 
 68 #掌握
 69 # info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
 70 # info_dic.update({‘a‘:1,‘name‘:‘Egon‘})  #有的话就是覆盖，没有的话就是添加
 71 # print(info_dic)
 72 
 73 # info_dic[‘hobbies‘]=[]
 74 # info_dic[‘hobbies‘].append(‘study‘)
 75 # info_dic[‘hobbies‘].append(‘read‘)
 76 # print(info_dic)
 77 
 78 #setdefault:key不存在则设置默认值，并且将默认值添加到values中
 79 #key存在则不设置默认，并且返回已经有的值
 80 
 81 # info_dic.setdefault(‘hobbies‘,[1,2])
 82 # print(info_dic)
 83 # info_dic.setdefault(‘hobbies‘,[1,2,3,4,5])
 84 # print(info_dic)
 85 
 86 # info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
 87 
 88 # {‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘,‘hobbies‘:[‘study‘]}
 89 # info_dic.setdefault(‘hobbies‘,[]).append(‘study‘)
 90 # print(info_dic)
 91 
 92 # {‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘,‘hobbies‘:[‘study‘,‘read‘]}
 93 # info_dic.setdefault(‘hobbies‘,[]).append(‘read‘)
 94 # print(info_dic)
 95 
 96 # {‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘,‘hobbies‘:[‘study‘,‘read‘,‘sleep‘]}
 97 # info_dic.setdefault(‘hobbies‘,[]).append(‘sleep‘)
 98 # info_dic.setdefault(‘hobbies‘,[]).append(‘read‘)
 99 # l=info_dic.setdefault(‘hobbies‘,[])
100 # print(l,id(l))
101 # print(info_dic,id(info_dic[‘hobbies‘]))
102 
103 # info_dic.setdefault(‘hobbies‘,‘a‘) #都可以，id都一样
104 # info_dic.setdefault(‘hobbies‘,{1})
105 # # info_dic.setdefault(‘hobbies‘,(2))
106 # l=info_dic.setdefault(‘hobbies‘,{})
107 # print(l,id(l))
108 # print(info_dic,id(info_dic[‘hobbies‘]))
109 
110 
111 #了解
112 # d=info_dic.copy()
113 # print(d)
114 # info_dic.clear()
115 # print(info_dic)
116 
117 # info_dic={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}
118 # d=info_dic.fromkeys((‘name‘,‘age‘,‘sex‘),None) #格式化，将values改成None,None可以是任何
119 # print(d)
120 # d1=dict.fromkeys((‘name‘,‘age‘,‘sex‘),None)
121 # d2=dict.fromkeys((‘name‘,‘age‘,‘sex‘),(‘egon‘,18,‘male‘))
122 # print(d1)
123 # print(d2)
124 #
125 # info=dict(name=‘egon‘,age=18,sex=‘male‘) #字典写法
126 # print(info)
127 
128 # info=dict([(‘name‘,‘egon‘),(‘age‘,18)]) #字典写法
129 # print(info)