python - 在现有的 python 字典键上添加更多值

Question

我是 python 的新手，我在制作字典时卡住了。请帮忙:)

这就是我的开始:

dict = {}
dict['a']={'ra':7, 'dec':8}
dict['b']={'ra':3, 'dec':5}

到目前为止一切都很完美。我得到:

In [93]: dict
Out[93]: {'a': {'dec':8 , 'ra': 7}, 'b': {'dec': 5, 'ra': 3}}

但是现在，如果我想向键“a”添加更多内容，我会这样做:

dict['a']={'dist':12}

然后它删除'a'之前的信息，我现在得到的是:

In [93]: dict
Out[93]: {'a': {'dist':12}, 'b': {'dec': 5, 'ra': 3}}

我想要的是:

In [93]: dict
Out[93]: {'a': {'dec':8 , 'ra': 7, 'dist':12}, 'b': {'dec': 5, 'ra': 3}}

有人可以帮忙吗？？

Answer 1

>>> d = {}
>>> d['a'] = {'ra':7, 'dec':8}
>>> d['b'] = {'ra':3, 'dec':5}
>>> d['a']['dist'] = 12
>>> d
{'a': {'dec': 8, 'dist': 12, 'ra': 7}, 'b': {'dec': 5, 'ra': 3}}

如果你想从另一个字典更新字典，使用update() :

Update the dictionary with the key/value pairs from other, overwriting existing keys.

>>> d = {}
>>> d['a'] = {'ra':7, 'dec':8}
>>> d['b'] = {'ra':3, 'dec':5}
>>> d['a'].update({'dist': 12})
>>> d
{'a': {'dec': 8, 'dist': 12, 'ra': 7}, 'b': {'dec': 5, 'ra': 3}}

此外，不要将 dict 用作变量名 - 它隐藏了内置的 dict 类型。看看可能会发生什么:

>>> dict(one=1)
{'one': 1}
>>> dict = {}
>>> dict(one=1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'dict' object is not callable