Python3 字典

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Python3 字典

字典是另一种可变容器模型，且可存储任意类型对象。
字典的每个键值(key=>value)对用冒号(:)分割，每个对之间用逗号(,)分割，整个字典包括在花括号({})中。

dictionary={"first":"Python","second":"VB.net","third":"C#"}
print(dictionary["first"])

字典中的值，可以是不同的数据类型
如

dictionary={"first":"Python","second":"VB.net","third":"C#","x":100,"y":20}
print(dictionary["x"]+dictionary["y"])

可添加键值对

dictionary={"first":"Python","second":"VB.net","third":"C#","x":100,"y":20}
dictionary["newKey"]="新建值对"
print(dictionary["newKey"])

可以修改字典中的值

dictionary={"first":"Python","second":"VB.net","third":"C#","x":100,"y":20}
dictionary["first"]=100
print(dictionary["first"])

删除键值对
如

dictionary={"first":"Python","second":"VB.net","third":"C#","x":100,"y":20}
del dictionary["x"]
print(dictionary)

遍历字典
如

dictionary={"first":"Python","second":"VB.net","third":"C#"}
for k,v in dictionary.items():
print("键："+k)
print("值："+v)

遍历字典中所有键
如

dictionary={"first":"Python","second":"VB.net","third":"C#"}
for k in dictionary.keys():
print("键："+k.title())

遍历字典中的所有值

dictionary={"first":"Python","second":"VB.net","third":"C#"}
for v in dictionary.values():
print("值："+v.title())

去除字典中的重复值
我们利用set函数，去除字典中的重复值

dictionary={"first":"Python","second":"VB.net","third":"C#","third2":"C#"}
for v in set(dictionary.values()):
print("值："+v.title())

dictionary={"first":"Python","second":"VB.net","third":"C#"}
dictionary2={"first2":"Python","second2":"VB.net","third2":"C#"}
dictionary3={"first3":"Python","second3":"VB.net","third3":"C#"}
dictionaries=[dictionary,dictionary2,dictionary3]
for dic in dictionaries:
print(dic)

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