作業：購物商城

商品展示，價格

買，加入購物車

付款，錢不夠

代碼如下：

import codecs
#登錄接口，用戶名密碼都正確登錄成功，否則失敗

def login(your_name,your_password):
    with open("user_file","r") as l:
        for line in l:
            user_name,user_password,user_balance=line.strip().split(":")
            if your_name == user_name and your_password == user_password:
                flag 
 
= 1
                break
            else:
                print("用戶名或密碼錯誤")
                flag = 0
    return flag

#商品展示列表
def show_goods():
    print(10*‘*‘ + "商品列表" + 10*"*")
    print(30 * "-")
    print("| 編號 | 名稱 | 價格 | 數量 | ")
    try:
        with codecs.open("goods_file","r","utf-8") as f1:
            
 
for line in f1:
                (goods_id,goods_name,goods_rate,goods_num) = line.strip().split(":")
                print(30 * "-")
                print(‘| %s | %s | %s | %s |‘ %(goods_id,goods_name,goods_rate,goods_num))
            print(30*"-")
        # print("購買商品請輸入產品編號/返回請輸入b/退出請輸入q")
        # the_num 
 
= input("請選擇：")
    except ValueError:
        pass

#展示購物車
def show_gouwuche(your_name):
    with codecs.open("gouwuche","r","utf-8") as f2:
        n = 0
        print(30 * "-")
        print("| 編號 | 名稱 | 數量 | 總價 |")
        for line in f2:
            user_name,goods_name,goods_num,goods_rate = line.strip().split(":")
            if user_name == your_name:
                n += 1
                print(30 * "-")
                print(" | %s | %s | %s | %s |" %(n,goods_name,goods_num,goods_rate))
        print(30*"-")

#查看當前用戶已購產品
def show_yigou(your_name):
    with codecs.open("yigoushangpin","r","utf-8") as f3:
        n = 0
        print(30*"-")
        print("| 編號 | 名稱 | 數量 | 總價 |")
        for line in f3:
            user_name,goods_name,goods_num,goods_rate = line.strip().split(":")
            if user_name == your_name:
                n += 1
                print(30*"-")
                print(‘| %s | %s | %s | %s |‘ %(n,goods_name,goods_num,goods_rate))
        print(30*"-")

#賬戶余數查看
def show_money(your_name):
    with open("user_file","r") as l:
        for line in l:
            user_name,user_password,user_blance = line.strip().split(":")
            if your_name == user_name:
                print("您當前賬戶余額為：%s" %user_blance)
                break


# 賬戶余額查看
def show_money(your_name):
    with open(‘user_file‘, ‘r‘) as l:
        for line in l:
            user_name, user_password, user_balance = line.strip().split(‘:‘)
            if your_name == user_name:
                print(‘您當前賬戶余額為:%s‘ % user_balance)
                break

#加入購物車，如果購物車中已經存在該商品則將商品數量相加，商品價格相加；如果購物車中不存在該商品，則添加到購物車中，並將可購買的庫存量
def add_gouwuche(n,your_name):
    with codecs.open("goods_file","r+","utf-8") as f1:
        for line1 in f1:
            goods_id,goods_name,goods_rate,goods_num = line1.strip().split(":")
            if n == goods_id:
                goods_quantity = input("請輸入數量：")
                #如果輸入的並非數字則不合法，輸入的數量大於庫存，均需要重新輸入
                while True:
                    if goods_quantity.isdigit():
                        if int(goods_num) < int(goods_quantity):
                            goods_quantity = input("您輸入的數量大於當前庫克數量，請重新輸入數量：")
                        else:
                            break
                    else:
                        goods_quantity = input("您輸入的不合法，請重新輸入數量：")
                with codecs.open("gouwuche","r+","utf-8") as f2:
                    for line2 in f2:
                        che_user_name,che_goods_name,che_goods_num,che_goods_rate = line2.strip().split(":")
                        #判斷當前選擇的商品是否在購物車存在，如果存在標誌位che_flag = 1
                        if your_name == che_user_name and goods_name == che_goods_name:
                            che_flag = 1
                            che_goods_num = str(int(che_goods_num) + int(goods_quantity))
                            che_goods_rate = str(int(che_goods_rate) + int(goods_rate)*int(goods_quantity))
                            old_line = line2
                            new_line = che_user_name + ":" + che_goods_name + ":" + che_goods_num + ":" + che_goods_rate + "\n"
                            break
                    #當前選擇的商品購物車中不存在，標誌位che_flag = 0
                    else:
                        che_flag = 0
                        che_goods_rate = str(int(goods_rate) * int(goods_quantity))
                        che_goods_num = goods_quantity
                        che_goods_name = goods_name
                        che_user_name = your_name
                        new_line = ("%s:%s:%s:%s\n" %(che_user_name,che_goods_name,che_goods_num,che_goods_rate))
                        #購物車中存在，則將購物車中的數量更新，總價格更新
                        if che_flag == 1:
                            f2.seek(0)
                            old_gouwuche = f2.read()
                            new_gouwuche = old_gouwuche.replace(old_line,new_line)
                            f2.seek(0)
                            f2.truncate()
                            f2.write(new_gouwuche)
                        #購物車中不存在，則在購物車中添加
                        elif che_flag == 0:
                            f2.seek(0)
                            old_gouwuche =f2.read()
                            new_gouwuche = old_gouwuche + new_line
                            f2.seek(0)
                            f2.truncate()
                            f2.write(new_gouwuche)
                #加入購物車後，將商品列表中的數量更新
                new_goods_num = str(int(goods_num) - int(goods_quantity))
                old_goods_line = line1
                new_goods_line = ("%s:%s:%s:%s\n" %(goods_id,goods_name,goods_rate,new_goods_num))
                f1.seek(0)
                old_goods_file = f1.read()
                new_goods_file = old_goods_file.replace(old_goods_line,new_goods_line)
                f1.seek(0)
                f1.truncate()
                f1.write(new_goods_file)
                goods_flag = True
                break
        else:
            goods_flag = False
            print("抱歉您選擇的商品不存在，請重新選擇")
        return goods_flag

#刪除購物車的商品
def del_gouwuche(del_gouwuche_num,your_name):
    with codecs.open("gouwuche","r+","utf-8") as f1:
        while True:
            n = 0
            for line in f1:
                user_name,goods_name,goods_num,goods_rate = line.strip().split(":")
                #判斷刪除的商品是否存在，若存在撒謊拿出標誌位del_flag = 1
                if user_name == your_name:
                    n += 1
                    if int(del_gouwuche_num) == n:
                        del_goods_name = goods_name
                        del_goods_num = goods_num
                        del_goods_line = line1
                        del_flag = 1
                        break
                #商品存在，進行刪除
                if del_flag == 1:
                    f1.seek(0)
                    gouwuche_file = f1.readlines()
                    gouwuche_file.remove(del_goods_line)
                    f1.seek(0)
                    f1.truncate()
                    for line in gouwuche_file:
                        f1.write(line)
                    #更新商品清單，將從購物車刪除的加到商品清單中
                    with codecs.open("goods_file","r+","utf-8") as f2:
                        for line2 in f2:
                            old_goods_line = list(line2.strip().split(":"))
                            old_line = line2.strip()
                            if old_goods_line[1] == del_goods_name:
                                old_goods_line[3] = str(int(old_goods_line[3])) + int(del_goods_num)
                                new_goods_line = old_goods_line
                                del_flag = 1
                                break
                        if del_flag == 1:
                            f2.seek(0)
                            new_line = ":".join(new_goods_line)
                            old_goods_file = f2.read()
                            new_goods_file = old_goods_file.replace(old_line,new_line)
                            f2.seek(0)
                            f2.truncate()
                            f2.write(new_goods_file)
                break
            #要刪除的商品不存在，標誌位del_flag = 0
            else:
                del_flag = 0
                print("您要刪除的商品不存在，請重新輸入編號！")
                break
    return del_flag

#支付購物車商品
def pay_gouwuche(gouwuche_num,your_name):
    with codecs.open("gouwuche","r+","utf-8") as f1:
        while True:
            n = 0
            for line1 in f1:
                user_name,goods_name,goods_num,goods_rate = line1.strip().split(":")
                #判斷刪除的商品是否存在，若存在刪除標誌位del_flag = 1
                if user_name == your_name:
                    n += 1
                    if int(gouwuche_num) == n:
                        pay_goods_name = goods_name
                        pay_goods_num = goods_num
                        pay_goods_rate = goods_rate
                        pay_goods_line = line1
                        #查看當前用戶余額是否能夠支付商品
                        with open("user_file","r+") as user_file:
                            for line in user_file:
                                user_name,user_password,user_balance = line.strip().split(":")
                                if your_name == user_name:
                                    old_balance_line = line
                                    new_balance = int(user_balance) - int(goods_rate)
                                    break
                            if new_balance < 0:
                                print("您的當前預余額不足,請充值後再支付！\n")
                                pay_flag = False
                                break
                            #大於等於0時，則可以支付，並更新賬戶余額
                            else:
                                pay_flag = True
                                new_balance_line = user_name + ":" + user_password + ":" + str(new_balance) + "\n"
                                user_file.seek(0)
                                old_user_file = user_file.read()
                                new_user_file = old_user_file.replace(old_balance_line,new_balance.line)
                                user_file.seek(0)
                                user_file.truncate()
                                user_file.write(new_user_file)
                                break
                    else:
                        pay_flag = ""
            #商品存在，支付成功後進行刪除
            if pay_flag == True:
                f1.seek(0)
                gouwuche_file = f1.readlines()
                gouwuche_file.remove(pay_goods_line)
                f1.seek(0)
                f1.truncate()
                for line in gouwuche_file:
                    f1.write(line)
                #更新已購買的商品清單，將已支付的商品加入到購買的清單中
                with codecs.open("yigoushangpin","r+","utf-8") as f2:
                    for line2 in f2:
                        old_yigou_line = list(line2.strip().split(":"))
                        old_line = line2.strip()
                        #當已購商品清單存在該商品購買記錄則將數量相加，總價格相加
                        if old_yigou_line[1] == pay_goods_name and old_yigou_line[0] == your_name:
                            old_yigou_line[2] = str(int(old_yigou_line[2]) + int(pay_goods_num))
                            old_yigou_line[3] = str(int(old_yigou_line[3]) + int(pay_goods_rate))
                            new_yigou_line = old_yigou_line
                            f2.seed(0)
                            new_line = ":".join(new_yigou_line)
                            old_yigou_file = f2.read()
                            new_yigou_file = old_yigou_file.replace(old_line,new_line)
                            f2.seed(0)
                            f2.truncate()
                            f2.write(new_yigou_file)
                            break
                    #當已購商品清單滅有購買記錄，則附加購買記錄
                    else:
                        f2.seek(0)
                        old_yigou_file = f2.read()
                        new_yigou_file = old_yigou_file + pay_goods_line
                        f2.seek(0)
                        f2.truncate()
                        f2.write(new_yigou_file)
                print("\n")
                print("恭喜你，支付成功！")
                break
            elif pay_flag == False:
                flag = True
                break
            #要刪除的商品不存在，標誌位del_flag = 0
            else:
                pay_flag = False
                print("您要支付的商品不存在，請重新輸入編號！")
                break
    return pay_flag

#賬戶充值
def add_money(blance_num,your_name):
    with open("user_file","r+") as f:
        for line in f:
            user_name,user_passwd,user_balance = line.strip().split(":")
            if user_name == your_name:
                old_user_line = line
                new_user_balance = str(int(user_balance) + int(balance_num))
                new_user_line = user_name + ":" + user_passwd + ":" + new_user_balance + "\n"
                break
        f.seek(0)
        old_user_file = f.read()
        new_user_file = old_user_file.replace(old_user_line,new_user_line)
        f.seek(0)
        old_user_file = f.read()
        new_user_file = old_user_file.replace(old_user_line,new_user_line)
        f.seek(0)
        f.truncate()
        f.write(new_user_file)

def main():
    your_name = input("請輸入用戶名：")
    your_password = input("請輸入密碼：")
    menu_num = ""
    #登錄,用戶名或密碼錯誤重新輸入
    while True:
        if login(your_name,your_password):
            print("歡迎%s登錄購物商城" %your_name)
            print(30 * "*")
            break
        else:
            your_name = input("請重新輸入用戶名：")
            your_password = input("請重新輸入密碼：")
    while True:
        print(30 * "*")
        print("歡迎來到主菜單，您可進行如下操作！")
        print(30 * "*")
        print("| 1 商品列表 | 2 查詢購物車 | 3  查看已購商品 | 4 賬戶余額 | q 退出商城 |")
        if menu_num == "":
            menu_num = input("請輸入：")
        #進入商品列表
        elif menu_num == "1":
            while True:
                show_goods()
                print("| 請輸入商品編號加入購物車 | 輸入b返回主菜單 | 輸入q退出商城 |")
                your_goods_num = input("請選擇：")
                print("\n")
                #判斷輸入的是否為純數字，如果是
                if your_goods_num.isdigit():
                    while add_gouwuche(your_goods_num,your_name):
                        #當商品加入購物車後直接返回給購物車
                        menu_num = "2"
                        break
                    break
                elif your_goods_num == ‘b‘:
                    menu_num = ""
                    break
                elif your_goods_num == "q":
                    print("您已退出商城！")
                else:
                    print("您輸入的不合法，請重新輸入！\n")
        #查看購物車
        elif menu_num == "2":
            while True:
                print(30 * "*")
                print("您當前購物車商品如下所示：")
                show_gouwuche(your_name)
                print("| 1 返回主菜單 | 2 刪除商品 | 3 支付商品 | q 退出商城 |")
                gouwuche_menu_num = input("請輸入：")
                print("\n")
                #返回主菜單
                if gouwuche_menu_num == ‘1‘:
                    menu_num = ‘‘
                    break
                #刪除商品
                elif gouwuche_menu_num == ‘2‘:
                    while True:
                        del_gouwuche_num = input("請輸入要刪除的商品編號，或者輸入b返回：")
                        if del_gouwuche_num == "b":
                            break
                        elif not del_gouwuche_num.isdigit():
                            print("您輸入的不合法，請重新輸入！\n")
                            continue
                        elif del_gouwuche(del_gouwuche_num,your_name):
                            print("刪除成功\n")
                            break
                #支付商品
                elif gouwuche_menu_num == "3":
                    while True:
                        pay_gouwuche_num = input("請輸入要支付的商品編號，返回請輸入b:")
                        if pay_gouwuche_num.isdigit():
                            if pay_gouwuche(pay_gouwuche_num,your_name):
                                break
                        elif pay_gouwuche_num == "b":
                            break
                        else:
                            print("您輸入的不合法，請重新輸入！")
                elif gouwuche_menu_num == "q":
                    print("您已退出商城!")
                    exit()
                else:
                    print("您輸入的不合法，請重新輸入\n")
        #查看已購買記錄
        elif menu_num == "3":
            print(30 * "*")
            print("您已購買商品如下所示：")
            show_yigou(your_name)
            print("| 輸入b返回主菜單 | 輸入q退出程序 |")
            while True:
                yigou_input = input("請輸入：")
                if yigou_input == "b":
                    menu_num = ""
                    print("\n")
                    break
                elif yigou_input == "q":
                    print("您已退出商城！\n")
                else:
                    print("你輸入的不合法，請重新輸入!\n")
        #查看賬戶信息
        elif menu_num == "4":
            while True:
                print(30 * "-")
                print("您的賬戶信息如下所示：")
                show_money(your_name)
                print("| 1 充值賬戶 | b 返回主菜單 | q 退出商城 |")
                money_num == input("請輸入：")
                if money_num == "1":
                    print(30 * "-")
                    add_money_num = input("請輸入充值金額，輸入b返回：")
                    if add_money_num.isdigit():
                        add_money_num = input("請輸入充值金額，輸入b返回：")
                        if add_money_num.isdigit():
                            add_money(add_money,your_name)
                            print("恭喜你，充值成功！\n")
                            continue
                        elif add_money_num == "b":
                            continue
                        else:
                            print("您輸入的不合法，請重新輸入！\n")
                            continue
                        elif money_num == "b":
                            menu_num = ""
                            break
                        elif money_num == "q":
                            print("您已退出商城!")
                            exit()
                        else:
                            print("您輸入的不合法，請重新輸入\n")
            elif menu_num == "q":
                print("您已退出商城!")
                exit()
            else:
                print("您的輸入不合法，請重新輸入!\n")

if __name__ == ‘__main__‘:
    main()

上面代碼是網上找的，準備自己好好寫一遍，開始的時候沒有什麽思路，裏面主要是對文件的操作，還有一些新的方法，都是常用的方法，但是平時自己不會用的。

day2、購物商城