你如何找出一个值属于哪个对象？

Question

Say I have a dictionary called dic:

dic = {"a":1, "b":2, "c":3}

And let's say I have some code, and later on, I provide the key dic["a"] to derive a value 1. How would I be able to inform the programme that the value 1 came from the key of "a" inside "dic", and not from say, a list, or another dic, and so on?

This is important because am writing a programme where there are many of the same values, but parts of the programme are going to run based upon where the value came from.

Thanks.

Answer 1

There is, as far as I know, no way to do what you're asking. Data retrieved from dictionaries and other sources have no knowledge of the key that they were associated with originally.

I think the cleanest method would be to have some kind of wrapper function that handles this for you and stores the data in an easy to use format:

from typing import Dict, NamedTuple

class Record(NamedTuple):
    amount: int
    source: str

def recording_get(dict: Dict[str, int], source: str) -> Record:
    return Record(dict[source], source)


dic = {"a":1, "b":2, "c":3}
rec = recording_get(dic, "a")
print(rec)  #  Prints Record(amount=1, source='a')