two week summary

from collections import Iterator
from collections import Iterabl

dic = {'a':"a","91a":"c"}

print(max(dic))   # 可迭代对象为字典时，取的是键

print(max("cd","ft"))

def sum1(n):
    sum1 = 0
    for i in range(n,0,-1):
        print(i)
        sum1 +=i
    return sum1
print(sum1(8))

# range()  # 是内置函数，产生一个定制的数字范围的整数序列，返回的是一个迭代对象，不能直接取值，通过for循环。
print(range(5),type(range(5)))
print(isinstance(range(5),Iterable))  # True
print(isinstance(range(5),Iterator))  # False
print("__iter__" in dir(range(5)))   # True
print("__next__" in dir(range(5)))  # False

range_iterator = range(5).__iter__()  # 将可迭代对象  转换成为 迭代器
# print(range_iterator.__next__())
# print(range_iterator.__next__())
# print(range_iterator.__next__())

while True:
    try:
        item = range_iterator.__next__()
        print(item)
    except StopIteration:
        break

li = [1,3,5,10]
print(li)

print(isinstance(li,Iterable)) # True