python 第12天作业

#写函数，，用户传入修改的文件名，与要修改的内容，执行函数，完成整个文件的批量修改操作
import os
name = input('document:')
context = input('context:')
fixcontext = input('fixcontext:')
def my_replace(name,context,fixcontext):
    with open(name,'r',encoding='utf-8') as read_f,
        open('name_swap','w',encoding='utf-8') as write_f:
            for line in read_f.readlines():
                write_f.write(line.replace(context,fixcontext))
    os.remove(name)
    os.rename('name_swap',name)
my_replace(name, context,fixcontext)
#写函数，检查用户传入的对象（字符串、列表、元组）的每一个元素是否含有空内容。
def notnone(*args):
    for i in args:
        if len(i) == 0:
            print(type(i),'为空')
        else:
            for j in i:
                if len(str(j)) == 0:
                    s = j
            print('%s中的有%s个元素为空' % (i,i.count(s)))
s = ''
l = [1,2,'','','',4,5]
t = ('',)
notnone(s,l,t)
# #写函数，检查传入字典的每一个value的长度,如果大于2，那么仅保留前两个长度的内容，并将新内容返回给调用者。
   # dic = {"k1": "v1v1", "k2": [11,22,33,44]}
   # PS:字典中的value只能是字符串或列表
def cut_dic_value(**kwargs):
    for i in kwargs.keys():
        if len(kwargs[i]) > 2:
            kwargs[i] = kwargs[i][:2]
    return kwargs
dic = {"k1": "v1v1", "k2": [11,22,33,44]}
print(cut_dic_value(**dic))

#用函数实现购物车程序
def login():
    num = 0
    while True:
        usr = input('user:')
        pwd = input('password:')
        if usr == 'egon' and pwd == '123':
            print('login success
welcome',usr)
            return True
        else:
            print('login fail')
            if num > 2:
                return False
            num += 1
def purch():
    usr_goods = []
    goods = {'apple':5,'pear':3,'tomato':6,'egg':2}
    while True:
        for key, value in goods.items():
            print('商品：{name} 价格：{price}'.format(name=key, price=value).center(30, '#'))
        select = input('请选择商品')
        if select not in goods:
            print('没有此商品')
            continue
        else:usr_goods.append({select:goods[select]})
        while True:
            num = input('请输入数量：')
            if num.isdigit():
                num = int(num)
                usr_goods[-1]['num'] = num
                print('购买成功')
                break
            else:
                print('非法输入，请的输入数字')
                continue
        ex = input('是否继续购买？1继续，2结算')
        if ex == '1':continue
        else:break
    return usr_goods

if login():
    print(purch())