迭代

用for循环遍历llist or tuple or dict称之为迭代

1. 迭代dict,默认是迭代key

people = {'name'：'zhoubo',  'age': 23, 'city': 'Guangzhou'}
for key in people:
    print(key)
#output
name
age
city

2. 迭代value

for value in people.values():
    print(value)

#output
zhuobo
23
Guangzhou

3. 同时迭代key and value

for k, v in people.items():
    print(k + ' : ' + v)

#output
name : zhuobo
age : 23
city : Guangzhou