Python之路 day2 初识字典

 #Author:ersa
 '''
 key-value 键值对
 字典是无序的，不需要下标，有key
 字典的查找、修改、添加、判断、删除
 '''

 info = {
     'stu1101': "TengLan Wu",
     'stu1102': "LongZe Luola",
     'stu1103': "XiaoZe Maliya",
 }

 #输出
 print("输出所有的key".center(50,'='))
 print(info.keys())
 print("=".center(70,'='))

 print("输出所有的 值".center(50,'='))
 print(info.values())
 print("=".center(70,'='))

 #循环输出键-值
 print("输出键-值".center(50,'='))
 for i in info:
     print(i,info[i])
 print("=".center(70,'='))

 #设置默认值：如果有key-value 则返回，没有则创建
 print("取key-value值，没有则创建".center(50,'='))
 info.setdefault("stu1106","Alex")
 print(info)
 print("=".center(70,'='))

 #查找
 print(info)
 print("查找".center(50,'='))
 print(info["stu1101"])

 #安全查找--->查找的值不存在时不会报错
 print("安全查找".center(50,'='))
 print(info.get('stu1104'))

 #判断
 print("判断key是否存在".center(50,'='))
 print('stu1104' in info)

 #修改
 print("修改".center(50,'='))
 print(info)

 info["stu1101"] = "武藤兰"
 #添加
 print("添加".center(50,'='))
 info["stu1104"] = "苍老师"
 print(info["stu1104"])

 #删除 Python--->通用删除del
 print("删除".center(50,'='))
 #del info["stu1101"]
 print(info)

 #字典删除
 print("字典删除".center(50,'='))
 #info.pop("stu1101")
 print(info)

 #随机删除
 print("随机删除".center(50,'='))
 #info.popitem()
 print(info)

 #字典转列表
 print("字典转列表".center(50,'='))
 print(info.items())
 print("=".center(70,'='))

 #update 更新字典
 b = {
     'stu1101':"alex",
     1:3,
     2:5
 }
 info.update(b)
 print("合并字典，有重合key，则更新".center(50,'='))
 print(info)
 print("=".center(70,'='))

 #初始化新的字典
 print("初始化新的字典".center(50,'='))
 c = dict.fromkeys([6,7,8],'test')
 print(c)
 print("=".center(70,'='))