python实现购物车程序

本文尝试用python实现简单的购物车程序。。。

基本要求：

用户输入工资，然后打印购物菜单
用户可以不断的购买商品，直到余额不够为止

退出时打印用户已购买的商品和剩余金额。。。

代码：

#!/usr/env python
#coding:utf-8

import re,math

def get_customer_salary():
    while True:
        salary=raw_input('Please input your monthly salary(a positive integer):')
        if __is_valid_num(salary):
            return int(salary)
        else:
            print '[warn] Please input a valid number!'

def __is_valid_num(num):
    p=re.compile(r'^\d+$')
    m=p.match(num)
    if m:
        return True
    else:
        return False

def get_customer_selection():
    while True:
        selection=raw_input('Please enter the goods number you want to buy:')
        if __is_valid_num(selection):
            if __is_a_valid_selection(int(selection)):
                return int(selection)
            else:
                print '[warn] Please enter a valid selection number'
        else:
            print '[warn] Please enter a valid number!\n'

def __is_a_valid_selection(selection):
    if 1<=selection<=get_total_amount_of_products():
        return True
    else:
        return False

def get_products_list():
    return {'Flower':50,'Perfume':300,'Shoes':600,'Clothing':800,'Alcohol':300,
             'Makeup':800,'Bike':1500,'Car':200000,'Apartment':5000000}

def get_total_amount_of_products():
    return len(get_products_list())

def mapping_type_code_for_products():
    return ['Flower','Perfume','Shoes','Clothing','Alcohol','Makeup','Bike','Car','Apartment']

def get_product_price(type_code):
    return get_products_list()[get_product_name(type_code)]

def get_product_name(type_code):
    return mapping_type_code_for_products()[type_code-1]

def get_lowest_price_of_products():
    price_list=[]
    for k,v in get_products_list().items():
        price_list.append(v)
    return min(price_list)

def get_highest_price_of_produces():
    price_list=[]
    for k,v in get_products_list().items():
        price_list.append(v)
    return max(price_list)

def still_can_buy_something(left_money):
    if left_money=product_price:
        return True
    else:
        return False

def time_needed_to_work_for_buying_products(salary,price):
    result=float(price)/salary
    return get_formatting_time(int(math.ceil(result)))

def get_formatting_time(months):
    if months<12:return ('%d months' % months)
    years=months/12
    months=months%12
    return ('%d years,%d months' % (years,months))

#主程序从这里开始
if __name__=='__main__':
    salary=get_customer_salary() #获取月工资
    total_money=salary
    shopping_cart=[] #初始化购物车
    while True:
        show_shopping_list() #打印购物列表
        #判断剩余资金是否能够购买列表中的最低商品
        if still_can_buy_something(total_money):
            selection=get_customer_selection() #获取用户需要购买的商品编号
            product_price=get_product_price(selection)#获取商品的价格
            product_name=get_product_name(selection)#获取商品的名称
            if total_money>=product_price:
                total_money-=product_price
                #打印购买成功信息
                print 'Congratulations!You bought a %s successfully!\n' % product_name
                shopping_cart.append(product_name)#将商品加入购物车
                print 'You still have %d RMB left\n' % total_money #打印剩余资金
                #判断是否还想购买其他商品
                if not still_want_to_buy_something():
                    print 'Thank you for coming!'
                    break
            else:
                #输出还需要工作多久才能购买
                format_time=time_needed_to_work_for_buying_products(salary,product_price-total_money)
                print 'Sorry,you can not afford this product!\n'
                print "You have to work '%s' to get it!\n" % format_time
                #判断是否还想购买其他商品
                if not still_want_to_buy_something():break
        else:
            print 'Your balance is not enough and can not continue to buy anything.'
            break
    #打印购物车列表
    print 'Now,your balance is %d,and\nYou have buy %s' % (total_money,shopping_cart)

（完）