用户欢迎界面,新用户,老用户,函数的重构,文件写入读取

import json   #引入一个名为json的函数,一般用的文件存储

def get_stored_username():
    filename='username.json'        # 将要读取的文件名称存储在变量filename中
    try:
        with open(filename) as f:     # 以读写的方式打开文件filename,并把这种功能赋值给 f

            username=json.load(f)   #把 f 的信息读取出来赋值给username
    except FileNotFoundError:
        return None
    else:
        return username

def get_new_username():
    username=input('what is your name:')
    filename='usernmae.json'
    with open(filename,'w') as f:      
        json.dump(username,f)      #把 username 的值存储到 f 中
        return username

def greet_username():
    username=get_stored_username()   #获取文件里是否有名称存在
    if username:
        print('welcome to home %s '%username)
    else:
        username=get_new_username()
        print('welcome to china')
greet_username()

实例: 用户的幸运数字

import json

def input_number():
    like_number=input('what is your number:')
    filename='like_number.json'
    with open(filename,'w') as f:
        json.dump(like_number,f)
        print('welcome to python %s'%like_number)
        
def like_new_number():
    like_number=get_like_number()
         
    if like_number==None:
        input_number()
    else:
        username=input('what is your name %s ?(yes or no)\n'%like_number)
        if username=='yes':
            print('%s welcome to home'%like_number)
        else:
            input_number()
            
def get_like_number():
    try:
        filename = 'like_number.json'
        with open(filename) as f:
            like_number=json.load(f)

    except FileNotFoundError:
        return None
    else:
        return like_number
    
like_new_number()

filename='akl.txt'

with open(filename) as f:

        for line in f:                                                                     line = f.read()    #直接读取

              print(line)     按行打印,打印的时候空一行                 print(line)

              print(line.rstrip())   消除空行

# 逐行读取