> On 30 Jun 2023, at 02:50, Andre Delfino <adelf...@gmail.com> wrote:
>
> A dict method to retrieve the key of a value from a bijective dict would have
> come in handy to me in several occasions:
>
>>>> names = {'one': 1}
>>>> names.inverse()[1]
> 'one'
>>>> names = {'one': 1, 'uno': 1}
>>>> names.inverse()[1]
> ValueError: dict is not bijective
>
> My usual use case is when both keys and values have simple types like
> int/str, like:
>
> {
> 'account-a': 123,
> 'account-b': 456,
> }
>
> Users may enter the account name, or the ID. The system works with the
> account ID (translating from the account name if needed), but when it needs
> to mention the account to the user, it shows the account name instead.
>
> I do understand that retrieval wouldn't be O(1).
In cases like this I have two dict one for each look up direction.
by_name = {}
by_id = {}
def add(name, id):
by_name[name] = id
by_id[id] = name
etc.
Barry
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