Python学习之路

#上节课复习
# l=[1,2,3,4,5]
# print(list(map(str,l)))
#reduce
# from functools import reduce
# l=[1,2,3,4,5]
# #reduce(func,l)
# res=reduce(lambda x,y:x+y,l,3)
# print(res)
#filter()
# name=[‘alex_sb‘,‘zzc‘]
# res=filter(lambda x:not x.endswith(‘sb‘),name)
# print(list(res))

# 文件操作
# f=open(‘test.py‘,‘w‘,encoding=‘utf8‘)
# # f.write(‘1111\n‘)
# # f.write(‘1111\n‘)
# # f.write(‘1111\n‘)
# f.write(‘amoshi‘)
#
# f.close()
#r+ w+ a+
# f=open(‘test.py‘,‘r+‘,encoding=‘utf8‘)
# f.write(‘hallo‘)    #覆盖第一行
#b模式
# f=open(‘test.py‘,‘rb‘,encoding=‘utf8‘)   #b的方式不能指定编码

# f=open(‘test.py‘,‘rb‘)
# data=f.read()
# #‘字符串‘--encode----->bytes
# #‘字符串‘--decode----->‘字符串‘
#
# print(data)  #b‘# halloi\r\n# afasfasfsf\r\n# fasfsf\r\n\xe4\xbd\xa0\xe5\xa5\xbd\xe5\x95\x8a‘
#print(data.decode(‘utf8‘)

# f=open(‘test.py‘,‘wb‘) #b的方式不能指定编码
# # f.write(‘1111\n‘) #错误
# f.write(bytes(‘1111\n‘,encoding=‘utf8‘))
# f.write (‘1111\n‘.encode(‘utf8‘))
# f=open(‘a.txt‘,‘r‘,encoding=‘latin-1‘)
# # print(f.encoding) #文件打开的编码
# data=f.read()
# print(data)
#f=open(‘test.py‘,‘r+‘,encoding=‘utf-8‘,newline=‘‘)#读取文件中真正的换行符号
# print(f.tell())
# print(f.readlines())
# f.seek(5)  #控制光标的移动   按字节处理
# print(f.tell())
# print(f.readlines())
# print(f.read())  # 按字符读取
# f.truncate(10)   #截取文件  在写文件
#
# f=open(‘seek.txt‘,‘rb‘ )
# print(f.tell())
# f.seek(10,0)  #从0开始数字节
# print(f.tell())
# f.seek(3,1)   #从xiangduiweizhi
# print(f.tell())

# f=open(‘seek.txt‘,‘rb‘ )
# print(f.tell())
# f.seek(10,2)  #从文件末尾
# print(f.tell())

# f=open(‘日志文件‘,‘rb‘)
# data=f.readlines()
# print(data[-1].decode(‘utf-8‘))
#f=open(‘日志文件‘,‘rb‘)

# for i in f.readlines():
#     print(i)
#循环文件的方式
# for i in f:
#     print(i.decode(‘utf8‘))

# for i in f:
#     offs=-10
#     while True:
#         f.seek(offs,2)
#         data=f.readlines()
#         if len(data)>1:
#             print(‘文件的最后一行%s‘ %(data[-1].decode(‘utf8‘)))
#             break
#         offs*=2

#迭代器和生成器
#  迭代器协议：对象必须提供一个next方法，执行该方法要么返回迭代中的下一项，要么就引起一个StopLteration异常,以终止迭代（只能往后走不能往前退）
#  可迭代对象：实现了迭代器协议的对象（如何实现：对象内部定义一个__iter__（）方法）
#  协议是一种约定，可迭代对象实现了迭代器协议，python内部工具（如 for循环 sum min max)

# l=[1,2,3]
# #for i in l:   #i_l=l.__iter__()  i_l.__next__()
# print(l[0])
#
# iter_l=l.__iter__() #生成可迭代对象
# print(iter_l.__next__())

# index=0
# while index<len(l):
#     print(l[index])
#     index+=1

# x=‘csf‘
# s=x.__iter__()
# print(s)
# print(s.__next__())
# print(s.__next__())
# print(s.__next__())

# s={1,2,3}
#
# # for i in s:
# #     print(i)
# iter_s=s.__iter__()
# print(iter_s)
# print(iter_s.__next__())

# dic={‘a‘:1,‘b‘:2,‘c‘:3}
# iter_d=dic.__iter__()
# print(iter_d.__next__())

# l=[‘die‘,‘erzi‘,‘sunzi‘,‘chongsunzi‘]
#
# iter_l=l.__iter__()
# print(iter_l)   #可迭代对象
# print(iter_l.__next__())
# print(iter_l.__next__())
# print(iter_l.__next__())
# print(iter_l.__next__())
# print(next(iter_l))   #调用iter_l.__next__()

#生成器

# x=
# x.__next__()

# def test():
#     yield 1  相当于__iter__()
#     yield 2
#     yield 3
#
# g=test()
# print(g)
# g.__next__()

#三元表达式
# name=‘zzc‘
# res=‘haha‘ if name==‘zzc‘ else ‘csf‘
# print(res)

#列表解析
# egg_list=[]
# for i in range(10):
#     egg_list.append(‘鸡蛋%s‘,%i)
# print(egg_list)

# l=[ ‘鸡蛋%s‘  %i for i in range(10)]
# l2=[‘鸡蛋%s‘ %i for i in range(10) if i>5]
# print(l)

# laomuji=(‘鸡蛋%s‘ %i for i in range(10 ))#生成器表达式
# print(laomuji)
# print(laomuji.__next__())

# l=[1,2,3,4,5,6]

# print(sum(i for i in range(1000000000000)))#生成器表达式
# import time
# def test():
#     print(‘haha‘)
#     print(‘haha2‘)
#     print(‘haha3‘)
#     yield ‘wo‘ #return
#     time.sleep(3)
#     print(‘haha4‘)
#     yield ‘gg‘
#
# res=test()
# print(res)
# print(res.__next__())
# print(res.__next__())
# def xiadan():
#     for i in range(1000):
#         yield ‘jidan‘
# csf=xiadan()
# zzc=csf.__next__()
# print(‘qujidan‘,zzc)

#eval(i)#转成字典

#生产者消费模型

# import time
# def producer():
#     ret=[]
#     for i in range(10000):
#         ret.append(‘包子%s‘ %i)
#     return ret
# def consumer(res):
#     for index,baozi in enumerate(res):
#         time.sleep(0.1)
#         print(‘第%s个人，吃了%s‘ %(index,baozi))
#
# res=producer()
# consumer(res)
# def test():
#     print(‘开始啦‘)
#     first=yield 1 #retuen1  first=None
#     print(‘第一次‘,first)
#     yield 2
#     print(‘第二次‘)
#
# t=test()
# res=t.__next__() #next(t)
# print(res)
# t.send(None)

# def producer():
#     ret=[]
#     for i in range(10000):
#         ret.append(‘包子%s‘ %i)
#     return ret
# def consumer(name):
#     print(‘我是%s,我要吃包子了‘ %name)
#     while True:
#         baozi=yield            #yield相当于return
#         print(‘%s 很开心的吧%s吃了‘ %(name,baozi))
# def producer():
#     c1 = consumer(‘陈淑芳‘)
#     c2 = consumer(‘张志成‘)
#     c1.__next__()
#     c2.__next__()
#     for i in range(10):
#         time.sleep(1)
#         c1.send(‘包子‘)
#         c2.send(‘baozi‘)
# producer()






#     for index,baozi in enumerate(res):
#         time.sleep(0.1)
#         print(‘第%s个人，吃了%s‘ %(index,baozi))
#
# res=producer()
# consumer(res)