在字典中使用 eval

Question

我想使用字典本身来评估字典键的值。例如：

dict_ = {'x': 1, 'y': 2, 'z':'x+y'}
dict_['z'] = eval(dict_['z'], dict_)
print(dict_)

当我这样做时，它在字典中包含了一堆不必要的东西。在上面的例子中，它打印：

{'x': 1, 'y': 2, 'z': 3, '__builtins__': bunch-of-unnecessary-stuff-too-long-to-include

Instead, in the above example I just want:

{'x': 1, 'y': 2, 'z': 3}

How to resolve this issue? Thank you!

Answer 1

Pass a copy of dict to eval():

dict_ = {"x": 1, "y": 2, "z": "x+y"}

dict_["z"] = eval(dict_["z"], dict_.copy())
print(dict_)

Prints:

{'x': 1, 'y': 2, 'z': 3}