圣诞节的整理前两周的内容2

一、b模式：

# f=open('1','rb')
# data=f.read()
# print(data)






# f=open('test1','wb')
# f.write(bytes('hello',encoding='utf-8'))   #编码方法1
# f.write('杨戬'.encode('utf-8'))   #编码方法2

 

 

二、迭代器和生成器：

#方法一
# ll=[1,2,3,4]
# for item in ll:
#     print(item)




# x='hello'
# iter_test=x.__iter__()
# # print(iter_test)
# print(iter_test.__next__())
# print(iter_test.__next__())
# print(iter_test.__next__())
# print(iter_test.__next__())
# print(iter_test.__next__())
#
# print(iter_test.__next__())




#方法二
# ll=[1,2,3,4]
# p=ll.__iter__()
# print(p.__next__())
# print(p.__next__())
# print(p.__next__())
# print(p.__next__())



#方法三
# p=[1,2,3,4]
# index=0
# while index<len(p):
#     print(p[index])
#     index+=1




# # 方法四：
# ll=[1,2,3,4,5]
# diedai_ll=ll.__iter__()
# while True:
#     try:
#         print(diedai_ll.__next__())
#     except StopIteration:
#         print('迭代完毕，循环终止')
#         break



# 生成器生成器！！！！


# p=[1,2,3,4,5]
# def test():
#     yield 1
#     yield 2
#     yield 3
# g=test()
# print(g)
# # 这时，g就可以直接用.__next__（）了
# print(g.__next__())
# print(g.__next__())
# print(g.__next__())






print(sum(x**2 for x in range(4)))