python练习——字典

1.字典定义

my_friend = { 'first_name' : 'lin', 'last_name' : 'feng','age' : 20, 'city' : 'xueyue' }
print(my_friend)

2.遍历字典

注：print()语句当中字符串拼接需将value强制转换为string

for key, value in my_friend.items():
     print(key + ':' + str(value) + '\n')

单独访问关键字：for key in my_friend.keys():或for key in my_friend:

单独访问值：for value in my_friend.values():

3.嵌套

（1）字典列表

my_friend_1 = { 'first_name' : 'Lin', 'lat_name' : 'feng','age' : 20, 'city' : 'xueyue' }
my_friend_2 = { 'first_name' : 'Tang', 'lat_name' : 'youyou','age' : 21, 'city' : 'tianchi' }
my_friend_3 = { 'first_name' : 'Jun', 'lat_name' : 'moxi','age' : 22, 'city' : 'longshang' }
my_friend_4 = { 'first_name' : 'Juangpu', 'lat_name' : 'long','age' : 22, 'city' : 'tianchi' }

my_friend = [my_friend_1,my_friend_2,my_friend_3,my_friend_4 ]

for person in my_friend:
 for key ,value in person.items():
  print(key + ':' + str(value) + '\n')
 print('\n\n')

（2）列表字典

my_friends = ['jummoxi','tangyouyou','huangpulong','qingmongxin' ]
myself = {'first_name' : 'Lin', 'last_name' : 'feng', 'friends':my_friends}
print(myself)
print('\n\nmy friends :\n')
for name in myself['friends']:
	print(name + '\n')

（3）字典嵌套字典

my_friend_2 = { 'first_name' : 'jun', 'lat_name' : 'moxi','age' : 22, 'city' : 'longshang' }
my_friend_4 = { 'first_name' : 'huangpu', 'lat_name' : 'long','age' : 22, 'city' : 'tianchi' }

myself = {'first_name' : 'Lin', 'last_name' : 'feng', 'my_bestfriends':my_friend_2,'my_roommate':my_friend_4}
print(myself)
print('\n\nmy friends :\n')
print(myself['my_bestfriends'] )
print('\n')
print(myself['my_roommate'])
print('\n')