如何用python打印购物小票 python基础打印购物小票 |
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如何用python打印购物小票 python基础打印购物小票
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1.基本需求 编写一个购物小程序，要求实现如下功能： （1）让用户输入工资； （2）输出购物菜单及产品价格； （3）计算用户是否可支付； （4）输出用户剩余的钱，问用户是否继续购物，如果选择继续，则继续进行，否则退出程序； （5）若钱不够，输出用户还需要工作多久才能买得起（这里暂不实现此功能）。 2.实现基本思路 基本思路可如下所示：
在编写程序的时候即以该思路为主线，具体细节下面再提及。 3.实现细节 基于友好用户界面的原则，实现的细节可总结如下： （1）用户输入工资时，如果输入的是非数字或没有输入，会有提示再次输入，而不会异常退出； （2）用户输入购买物品时，如果输入的是非商品索引或非quit退出时，会有提示再次输入，而不会异常退出； （3）每添加商品到购物列表后，会提示用户当前所剩余的money； （4）用户选择退出时，会打印用户的购物清单，同时输出用户剩余的money； （5）总的原则是，程序在执行过程中不会有异常情况出现，即使用户输入非法字符。 4.实现代码与注释 基于上述需求的实现代码如下： #!/usr/bin/env python import sys market = [ ['Xiaomi Phone', 2400], ['Iphone', 6000], ['Computer', 3800], ['Ipad', 1800], ['Core Python', 69], ['Router', 109] ] shop_list = []#The shopping list of the buyer. while True: salary = raw_input('Please input your salary per month:').strip() if not salary.isdigit(): print 'Please enter your salary.' continue salary = int(salary) print "Welcome to our market!You can buy something cool here, or you can enter 'quit' to left.\n" break #Upon:input the salary per month.输入工资同时避免异常情况。 while True: print 'The goods we serve are as follow:' for goods in market: print market.index(goods),goods[0],goods[1] #Upon:print the goods list. choice = raw_input('What do you want to buy?') if choice == 'quit':#'quit' system print '\nYour shopping list are as follow:' for goods in shop_list: print goods[0],goods[1] print 'Now you have %d left.' % (salary) sys.exit('Goodbye!') elif len(choice) == 0:#'enter' system continue #实际上'luanma' system和'enter' system可以只用前者进行替代，这里只是想输出不同提示而已。 （即输入乱码时会提示，输入enter时不进行提示。） if not choice.isdigit():#'luanma' system，即如果用户输入非数字时，会有提示 print 'Please input the right choice.(Number to buy things and quit to quit.)\n' continue #Upon: 'quit' system , 'enter' system and 'luanma' handle system. choice = int(choice) if choice >= len(market): print 'Could not find the item, try again!\n' continue pri = market[choice] #Upon:To check if the number is legal.确认输入的数字是否在合法范围内 pri = market[choice] if pri[1] 直接输入'Enter'时会有提示 Please input your salary per month:klkdf Please enter your salary. ===>输入乱码时也会有提示 Please input your salary per month:10000 Welcome to our market!You can buy something cool here, or you can enter 'quit' to left. The goods we serve are as follow: ===>先打印了一个商品菜单 0 Xiaomi Phone 2400 1 Iphone 6000 2 Computer 3800 3 Ipad 1800 4 Core Python 69 5 Router 109 What do you want to buy?0 ===>正确输入商品索引号，会提示当前用户购物信息 You have added Xiaomi Phone to your shopping list, and you have 7600 left. The goods we serve are as follow: 0 Xiaomi Phone 2400 1 Iphone 6000 2 Computer 3800 3 Ipad 1800 4 Core Python 69 5 Router 109 What do you want to buy? ===>只输入'Enter'时，不会有提示输出，但会再次打印商品菜单 The goods we serve are as follow: 0 Xiaomi Phone 2400 1 Iphone 6000 2 Computer 3800 3 Ipad 1800 4 Core Python 69 5 Router 109 What do you want to buy?3 You have added Ipad to your shopping list, and you have 5800 left. The goods we serve are as follow: 0 Xiaomi Phone 2400 1 Iphone 6000 2 Computer 3800 3 Ipad 1800 4 Core Python 69 5 Router 109 What do you want to buy?eqwer ===>输入乱码时，会有提示，并接受再次输入 Please input the right choice.(Number to buy things and quit to quit.) The goods we serve are as follow: 0 Xiaomi Phone 2400 1 Iphone 6000 2 Computer 3800 3 Ipad 1800 4 Core Python 69 5 Router 109 What do you want to buy?9 ===>输入不在合法范围内的数字时，也会有提示 Could not find the item, try again! The goods we serve are as follow: 0 Xiaomi Phone 2400 1 Iphone 6000 2 Computer 3800 3 Ipad 1800 4 Core Python 69 5 Router 109 What do you want to buy?quit ===>正常退出，会打印用户总的购物清单信息 Your shopping list are as follow: Xiaomi Phone 2400 Ipad 1800 Now you have 5800 left. Goodbye!相对来说，用户界面还是比较友好的，因为不会有太大的异常情况出现，同时也实现了基本的需求。 |
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