Python学习day2作业总结

为了以后更好更快速的复习，此博客记录我对作业的总结。对于基础作业，我认为最重要的是过程，至于实现是不是完美，代码是不是完美，虽然重要，但是作业过程中，用到的知识点是值得总结和整理的。

一.购物车：

1. 商品信息- 数量、单价、名称
2. 用户信息- 帐号、密码、余额
3. 用户可充值
4. 购物历史信息
5. 允许用户多次购买，每次可购买多件
6. 余额不足时进行提醒
7. 用户退出时 ，输出当次购物信息
8. 用户下次登陆时可查看购物历史
9. 商品列表分级显示

思路：

1.此作业是day1作业的结合体；
2.用户登录是否首次，分为新用户和旧用户；
3.旧用户查看是否有购物历史；
4.购买时可输入购买数量；
5.余额大于等于购买商品花费则购买成功，购买成功记录购买信息；
6.余额小于购买商品花费则提示充值，要求输入充值金额；
6.购物车自动整理购物商品与花费；
7.可随时查看购物车；

基本流程图：

代码：

cat shopping_cart.py

#!/usr/bin/env python
# _*_coding:utf-8_*_
'''
* Created on 2016/10/18 22:01.
* @author: Chinge_Yang.
'''
import os
import getpass
import datetime
menu = {
"Mobile phone": [
("Iphone7", 6188),
("Iphone7 plus", 7888),
("Xiaomi5", 2888)
],
"Car": [
("Audi Q5", 490000),
("Ferrari 488", 4888888)
],
"Drink": [
("Milk", 59),
("Coffee", 30),
("Tea", 311)
]
}
user_file = "user.txt"
shopping_log = "shopping.log"
money = 0   #初始金额
all_cost = 0
shopping_cart = {}
exit_user_flag = False
exit_flag = False
exsit_flag = False
if not os.path.exists(user_file):
f = open(user_file,'w')
f.close()
if not os.path.exists(shopping_log):
f = open(shopping_log,'w')
f.close()
def show_shopping_cart ():    #显示购物车，更新用户信息，exit前使用
#显示购物车信息
print("You purchased products as below".center(50,"*"))
print("%-20s %-15s %-10s %-20s" %("Goods","Price","Number","Cost"))
for key in shopping_cart:
p_name = key[0]
p_price = int(key[1])
p_number = int(shopping_cart[key])
print("%-20s %-15s %-10s \033[32;1m%-20s\033[0m" %(p_name,p_price,p_number,p_price*p_number))
print("End".center(50,"*"))
print("%-20s %-15s %-10s \033[32;1m%-20s\033[0m" %("You total cost:","","",all_cost))
print("Your balance is [\033[32;1m%s\033[0m]" % money)
if new_user is True:
# 将新用户信息写入到用户文件中
file = open(user_file, "a")
file.write("%s %s %s\n" % (user_name, user_passwd, money))  # 用户、密码、金钱存入用户文件
file.close()
else:
if old_money != money:  #充值或买了东西
# 将旧用户信息更新到用户文件中
old_user_info = "%s %s %s" % (user_name, user_passwd, old_money)
new_user_info = "%s %s %s" % (user_name, user_passwd, money)
with open(user_file) as file:
info = file.read()
new_info = info.replace(old_user_info,new_user_info)
with open(user_file,"w") as file:
file.write(new_info)
while exit_user_flag is not True:
#输入用户密码
user_name = input("Please input your name:").strip()
#user_passwd = input("Please input your password:").strip()
user_passwd = getpass.getpass("\033[1;33mPlease input your password:\033[0m")
if user_name == '' or user_passwd == '':
continue
elif ' ' in user_name:
print("\033[31;1mNot allowed to contain spaces!\033[0m")
continue
#查看是否存在于用户数据库
user_check = open(user_file)
for l in user_check:
l = l.split()
user = l[0]
passwd = l[1]
if user_name == user:   #老用户
new_user = False    #标记为老用户
money = int(l[2])   #记录用户余额
old_money = money   #旧余额
if not passwd == user_passwd:
print ("\033[1;31mYour password is error!\033[0m".center(50,"*"))
else:
print ("\033[1;31mWelcome to go shopping!\033[0m".center(50,"-"))
exit_user_flag = True
break
else:
new_user = True #标记为新用户
exit_user_flag = True
user_check.close()  #关闭
if not new_user:    #旧用户
#读取购物历史，判断是否有此用户记录
file = open(shopping_log)
for line in file:
line = line.split()
line_user = line[0]
if line_user == user_name:  #存在记录
exsit_flag = True
break   #跳出检测
file.close()
if exsit_flag is True:   #内容不为空
#只有输入y或者yes才读取显示购物历史，否则不显示
print("Input \033[1;33m[y|yes]\033[0m to view your purchase history,\033[1;33m[others]\033[0m means not.")
see_history = input("Please input:").strip()
if see_history == "y" or see_history == "yes":
# 显示用户购物历史
# output = os.system("grep %s %s" %(user_name,shopping_log))
# print(output.read())
print("User %s shopping history:" % user_name)
print("%-20s %-15s %10s %20s" %("Username","datetime","Number","Goods"))
file = open(shopping_log)
for line in file:
line = line.split("\t")
line_user = line[0]
if line_user == user_name:  #存在记录
print("%-10s %-15s %10s %20s" % (line[0],line[1],line[2],line[3].strip()))
file.close()
else:
print("You are not to view your purchase history!")
print("-".center(50,"-"))
one_layer_list = [] #一级菜单
while True:
while True:
#打印各类菜单
print("Species list".center(50,"-"))
for index, item in enumerate(menu):
print("\033[32;1m%d\033[0m --> %s" % (index, item))
one_layer_list.append(item)
print("End".center(50,"-"))
print("[q|b] to quit")
once_choice = input("Input your choice:").strip()
if once_choice.isdigit():   #输入数字
once_choice = int(once_choice)
if 0 <= once_choice < len(menu):    #输入正确数字
print("---->Enter \033[32;1m%s\033[0m" %(one_layer_list[once_choice]))
two_layer_list = menu[one_layer_list[once_choice]]
exit_flag = False   #重新进入二级商品菜单
break   #跳出循环，往下走
else:
print("\033[31;1mNumber out of range, please enter again!\033[0m")
else:
if once_choice == "b" or once_choice == "back" or once_choice == "q" or once_choice == "quit":
show_shopping_cart()
exit("Bye,thanks!".center(50,"#"))
print("\033[31;1mPlease enter the Numbers!\033[0m")
while exit_flag is not True:
#显示二级商品菜单
print("Product list".center(50,'-'))
for item in enumerate(two_layer_list):
index = item[0]
p_name = item[1][0]
p_price = item[1][1]
print("%s.%-20s %-20s" %(index,p_name,p_price))
print("End".center(50,'-'))
print("[q|quit] to quit;[b|back] to back")
user_choice = input("Please choice the product:").strip()
if user_choice.isdigit():   #输入数字
user_choice = int(user_choice)
if 0 <= user_choice < len(two_layer_list):
product_number = input("Please input the number of product:").strip()   #输入个数
if product_number.isdigit():
product_number = int(product_number)
else:
continue    #重新选择商品和个数
p_item = two_layer_list[user_choice]
p_name = p_item[0]  #商品名
p_price = int(p_item[1])    #商品价格
new_added = {}
if p_price*product_number <= money: #能付款，表示购买成功
new_added = {p_item:product_number}
#整理购物车个数显示总数
for k, v in new_added.items():
if k in shopping_cart.keys():
shopping_cart[k] += v
else:
shopping_cart[k] = v
money -= p_price * product_number
all_cost += p_price * product_number
print("Added [\033[32;1m%d\033[0m] [\033[32;1m%s\033[0m] into shopping cart,"
"your balance is [\033[32;1m%s\033[0m]" % (product_number,p_name,money))
with open(shopping_log,"a") as file:
log = "%s\t\"%s\"\t%d\t\"%s\"\n" %(user_name,datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S'),product_number,p_name)
shopping_history = file.write(log)
else:
#钱不够时，提示充值
print("Your balance is [\033[31;1m%s\033[0m],cannot afford this.." % money)
while True:
user_charge = input("Do you want to charge more money?[\033[32;1my|n|b]\033[0m").strip()
if user_charge == "y" or user_charge == "yes":
charge_number = input("Please input your top-up amount:").strip()
if charge_number.isdigit():
charge_number = int(charge_number)
money += charge_number  #充值成功
print("Your balance is [\033[32;1m%s\033[0m]" % money)
else:
print("Your input is not number!")
continue
break
elif user_charge == "n" or user_charge == "no" or user_charge == "b" or user_charge == "back":
break   #放弃充值
else:
if user_choice == "q" or user_choice == "quit":
show_shopping_cart()
exit("Bye,thanks!".center(50,"#"))
elif user_choice == "c" or user_choice == "check":
print("You purchased products as below".center(50,"*"))
print("%-20s %-15s %-10s %-20s" %("Goods","Price","Number","Cost"))
for key in shopping_cart:
p_name = key[0]
p_price = int(key[1])
p_number = int(shopping_cart[key])
print("%-20s %-15s %-10s \033[32;1m%-20s\033[0m" %(p_name,p_price,p_number,p_price*p_number))
print("End".center(50,"*"))
print("%-20s %-15s %-10s \033[32;1m%-20s\033[0m" %("You total cost:","","",all_cost))
print("Your balance is [\033[32;1m%s\033[0m]" % money)
elif user_choice == "b" or user_choice == "back":
exit_flag = True
else:
print("Your input is error!")

总结：

1.用到的基础知识点不少，不仅复习了day1知识，更灵活运用了列表、字典、元组等；
2.购物车还可以再完美，比如增加商品列表固定排序（如果使用json，我不知道怎么用），增加余额充值接口（使用信用卡）等；
3.对于复杂一些的需求，层次要分明，条理清晰，才能使自己逻辑思维鲜明；