dict字典的用法

在用dict遇到了一些困难，记一下。

代码1：

books={"倚天屠龙记":{"id":1,"price":100},
       "好吗好的":{"id":2,"price":200},
       "告别薇安":{"id":3,"price":300},
       "穆斯林的葬礼":{"id":4,"price":400}
       }
for i in books:
    print(i)

结果：

倚天屠龙记
好吗好的
告别薇安
穆斯林的葬礼

代码2：

books={"倚天屠龙记":{"id":1,"price":100},
       "好吗好的":{"id":2,"price":200},
       "告别薇安":{"id":3,"price":300},
       "穆斯林的葬礼":{"id":4,"price":400}
       }
for i in books:
    print(books[i])

结果：

{'id': 1, 'price': 100}
{'id': 2, 'price': 200}
{'id': 3, 'price': 300}
{'id': 4, 'price': 400}

代码3：

books={"倚天屠龙记":{"id":1,"price":100},
       "好吗好的":{"id":2,"price":200},
       "告别薇安":{"id":3,"price":300},
       "穆斯林的葬礼":{"id":4,"price":400}
       }
for i in books:
    print(books[i]["id"])

结果：

1
2
3
4

代码4：

books={"倚天屠龙记":{"id":1,"price":100},
       "好吗好的":{"id":2,"price":200},
       "告别薇安":{"id":3,"price":300},
       "穆斯林的葬礼":{"id":4,"price":400}
       }
for i in books:
    print(books[i]["price"])

结果：

100
200
300
400