自学Python从入门到放弃，14

嵌套

peoples = []  ##创建人群的空列表
for people_s in range(30):##range（）返回一系列数字，重复这个循环多次
  new_people = {'name':'zhangsan','age':'25','city':'beijing'}##每次循环时，创建一个人物
  peoples.append(new_people)##将其添加到列表末尾

for people in peoples[:5]:##使用切片打印出前五个人
  print(people)
print('...')
print('The number of :',str(len(peoples)))##打印列表长度，以证实创建了30个人

{'name': 'zhangsan', 'age': '25', 'city': 'beijing'}
{'name': 'zhangsan', 'age': '25', 'city': 'beijing'}
{'name': 'zhangsan', 'age': '25', 'city': 'beijing'}
{'name': 'zhangsan', 'age': '25', 'city': 'beijing'}
{'name': 'zhangsan', 'age': '25', 'city': 'beijing'}
...
The number of : 30
>>> 

这些人都叫相同的名字，年龄，城市，每个人都是独立的，可以独立的修改每个人。

在这里插入代码片peoples = []
for people_s in range(30):
  new_people = {'name':'zhangsan','age':'25','city':'beijing'}
  peoples.append(new_people)


for people in peoples[0:3]:
  if people['name'] == 'zhangsan':
     people['name'] = 'lisi'
     people['age'] == '22'
     people['city'] == 'shanghai'

for people in peoples[:5]:
  print(people)
print('...')
print('The number of :',str(len(peoples)))


{'name': 'lisi', 'age': '25', 'city': 'beijing'}
{'name': 'lisi', 'age': '25', 'city': 'beijing'}
{'name': 'lisi', 'age': '25', 'city': 'beijing'}
{'name': 'zhangsan', 'age': '25', 'city': 'beijing'}
{'name': 'zhangsan', 'age': '25', 'city': 'beijing'}
...
The number of : 30
>>> 

扩展循环，添加elif代码块，

peoples = []
for people_s in range(30):
  new_people = {'name':'zhangsan','age':'25','city':'beijing'}
  new_people2 = {'name':'lisi','age':'55','city':'shandong'}
  peoples.append(new_people)
  peoples.append(new_people2)

for people in peoples[0:10]:
  if people['name'] == 'zhangsan':
     people['name'] = 'lisi'
     people['age'] = '22'
     people['city'] = 'shanghai'
  elif people['name'] == 'lisi':
     people['name'] = 'wangwu'
     people['age'] = '27'
     people['city'] = 'guangzhou'

for people in peoples[:10]:
  print(people)
print('...')
print('The number of :',str(len(peoples)))

{'name': 'lisi', 'age': '22', 'city': 'shanghai'}
{'name': 'wangwu', 'age': '27', 'city': 'guangzhou'}
{'name': 'lisi', 'age': '22', 'city': 'shanghai'}
{'name': 'wangwu', 'age': '27', 'city': 'guangzhou'}
{'name': 'lisi', 'age': '22', 'city': 'shanghai'}
{'name': 'wangwu', 'age': '27', 'city': 'guangzhou'}
{'name': 'lisi', 'age': '22', 'city': 'shanghai'}
{'name': 'wangwu', 'age': '27', 'city': 'guangzhou'}
{'name': 'lisi', 'age': '22', 'city': 'shanghai'}
{'name': 'wangwu', 'age': '27', 'city': 'guangzhou'}
...
The number of : 60
>>> 

在字典中存储字典

people = {
  'police':{
    'first':'zhang',
    'last':'qiang',
    'age':'24',
    'city':'shanghai',
    },
  'doctor':{
    'first':'liu',
    'last':'ying',
    'age':'23',
    'city':'guangzhou',
    },
}

for people_occupation, people_info in people.items():
  print('\npeople_occupation:'+ people_occupation)
  name = people_info['first']+''+people_info['last']
  age_s = people_info['age']
  city_s = people_info['city']

  print('\tname:'+name)
  print('\tage:'+age_s)
  print('\tcity:'+city_s)
  
people_occupation:police
	name:zhangqiang
	age:24
	city:shanghai

people_occupation:doctor
	name:liuying
	age:23
	city:guangzhou
>>>