字典操作： 字典是一种key-value的数据类型， 字典的特性： dict 是无序的 key必须是唯一的，天生去重 info = { 'stu1101':"brace"; 'stu1102':"Kitty"; 'stu1103':"Lucy" } print(info) print(info['stu1101']) 输出： {'stu1101': 'brace', 'stu1102': 'Kitty', 'stu1103': 'Lucy'} brace 查找： info[stu1101] #如果key不存在会报错 info.get("stu1101") #有则返回，否组不返回 修改： info['stu1101']="你好" 增加： info['stu1104']="你好" 删除： del info['stu1101'] info.pop('stu1101') info.popitem() #随机删除 多级字典嵌套及操作： 省市县： china_name = { "安徽省":{"城市":["合肥"," 安庆","黄山","芜湖","池州"]}, "上海市":{"城市":["杨浦"," 闵行","浦东","长宁","黄埔"]}, "江苏省":{"城市":["南京"," 苏州","无锡","常州","苏北"]} }
print(china_name) print(china_name["安徽省"]) print(china_name.keys()) print(china_name.values()) 输出 {'安徽省': {'城市': ['合肥', ' 安庆', '黄山', '芜湖', '池州']}, '上海市': {'城市': ['杨浦', ' 闵行', '浦东', '长宁', '黄埔']}, '江苏省': {'城市': ['南京', ' 苏州', '无锡', '常州', '苏北']}} {'城市': ['合肥', ' 安庆', '黄山', '芜湖', '池州']} dict_keys(['安徽省', '上海市', '江苏省']) dict_values([{'城市': ['合肥', ' 安庆', '黄山', '芜湖', '池州']}, {'城市': ['杨浦', ' 闵行', '浦东', '长宁', '黄埔']}, {'城市': ['南京', ' 苏州', '无锡', '常州', '苏北']}])
info = { 'stu1101': "brace", 'stu1102': "Kitty", 'stu1103': "Lucy", } #setdefault 如果key存在，保持当前的，如果不存在，则新增并将默认值赋值。 info.setdefault("stu1101","xxxxxxxxx") print(info) info.setdefault("stu1104","xxxxxxxxx") print(info) {'stu1101': 'brace', 'stu1102': 'Kitty', 'stu1103': 'Lucy'} {'stu1101': 'brace', 'stu1102': 'Kitty', 'stu1103': 'Lucy', 'stu1104': 'xxxxxxxxx'} update 如果有重复的key增覆盖value,不重复的新增； info = { 'stu1101': "brace", 'stu1102': "Kitty", 'stu1103': "Lucy", } b = { "stu1101":"hello", "stu1104":"SSSSS", "stu1105":"FFFFFF" } info.update(b) print(info) print(info.items()) #将字典元素转化为列表元素 输出： {'stu1101': 'hello', 'stu1102': 'Kitty', 'stu1103': 'Lucy', 'stu1104': 'SSSSS', 'stu1105': 'FFFFFF'} dict_items([('stu1101', 'hello'), ('stu1102', 'Kitty'), ('stu1103', 'Lucy'), ('stu1104', 'SSSSS'), ('stu1105', 'FFFFFF')]) 初始化一个字典，key设定为设置项，值为初始化值test c = dict.fromkeys([5,6,7],"test") print(c) {5: 'test', 6: 'test', 7: 'test'} c = dict.fromkeys([5,6,7],[1,{2:"ss"},2]) print(c) c[6][1][2]="Brace" print(c) 输出： {5: [1, {2: 'ss'}, 2], 6: [1, {2: 'ss'}, 2], 7: [1, {2: 'ss'}, 2]} {5: [1, {2: 'Brace'}, 2], 6: [1, {2: 'Brace'}, 2], 7: [1, {2: 'Brace'}, 2]} for i in c: #高效，直接循环； print(i,c[i]) 输出： 5 [1, {2: 'Brace'}, 2] 6 [1, {2: 'Brace'}, 2] 7 [1, {2: 'Brace'}, 2] for k,v in c.items(): #由把字典转列表的过程，数据量大，效率低。 print(k,v) 5 [1, {2: 'Brace'}, 2] 6 [1, {2: 'Brace'}, 2] 7 [1, {2: 'Brace'}, 2]
作业： 用户入口： 1. 商品信息存在文件里 2. 已够商品，余额记录 商家入口 2. 可以添加商品，修改商品价格 作业： 启动程序后，让用户输入工资，然后打印商品列表 运行用户根据商品编号购买商品 用户选择商品后，检查余额是否够，够直接扣款，不够就提醒 可随时退出，退出时，打印已购买商品和余额 # Author:Brace Li import sys while True: salary = input("pls input your salary:") if salary.isdigit(): salary = int(salary) break
products_list = [ ("Iphone",5800), ("Mac Pro",9800), ("Bike",800), ("Watch",10600), ("Book",45) ] product_box = [] while True: product_id = [] for i,v in enumerate(products_list): print(i, v) product_id.append(i) while True: pro_num = input("select product:") if not pro_num.isdigit(): print("Error: >> Product number error!") continue product_num = int(pro_num) if product_num in product_id: break else: print("Error: >> Product number error!") continue product_box.append(products_list[product_num]) print("the product '%s' had been selected successfully" %products_list[product_num][0]) print() print("*" * 80) print("1. Exit System, 2.Continue, 3.Charge") print("*" * 80) while True: customer_action = input("select>>") if not customer_action.isdigit(): print("Error: Input error!") continue customer_action = int(customer_action) if not customer_action in (1,2,3): print("Error: Input error!") continue if customer_action == 1: sys.exit() elif customer_action == 2: break else: print(product_box) total_charge = 0 print("*" * 40) for n in list(set(product_box)): print("|| %s || %d ||" %(n[0],product_box.count(n))) print("*" * 40) total_charge += n[1]*product_box.count(n) print("Product total price: %d" %total_charge) print("*" * 40) if salary > total_charge: balance = salary - total_charge print("Charging Successfully !!!!!") else: balance = salary print("Charging fail, salary not enough !!!!!") print("balance: %d" % balance) sys.exit()