Python学习笔记：字典

封面

字典

定义：能够成队储存元素的序列

格式：字典名 = {key1:value1,key2:value2,……}

特性：每个键(key)都有一个与之关联的值(value)

创建字典

方法一：

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# 通过直接赋值的方式创建一个字典
sport = {"John":"soccer","Mike":"volleyball","Bob":"baseball","Amy":"ping-pong"}

方法二：

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# 创建一个空的字典，然后为其赋值
sport = {}
sport["John"] = "soccer"
sport["Mike"] = "volleyball"
sport["Bob"] = "baseball"
sport["Amy"] = "ping-pong"

查找字典元素

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scores = {"语文":88, "数学":90, "英语":85,
          "物理":87, "化学":75, "政治":93,
          "地理":88, "生物":98, "历史":100,
          "体育":87, "音乐":88, "美术":69}
print("我的化学成绩:", scores["化学"])
print("我的生物成绩:", scores.get("生物"))
print("我的信息成绩:", scores.get("信息"))

直接根据key查找value：dict[key]

使用get函数查找：dict.get(key)

编辑字典元素

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list_books = {"史记":"司马迁",
              "红与黑":"司汤",
              "悲惨世界":"雨果",
              "西游记":"吴承恩",
              "本草纲目":"李时珍"}
list_books["昆虫记"] = "法布尔"
list_books["水浒传"] = "施耐庵"
list_books["红与黑"] = "司汤达"
print(list_books)

反向查找字典元素

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id_name = {"01001":"小张",
           "01005":"小王",
           "01008":"小林",
           "01015":"小李",
           "01020":"小孔",
           "01035":"小何"}
name_id = {}
for id,name in id_name.items():
    name_id[name] = id
print("小李的学号:",name_id["小李"])

End