[Python-ideas] An identity dict

[Lie Ryan]

On 05/31/10 00:23, Benjamin Peterson wrote:
> Lie Ryan <lie.1296 at ...> writes:
>> what's wrong with dict[id(key)] = foo?
> 
> For one, you can't get the value of the key out of the dict.

mydict[id(key)] = (key, value)

>> that their id() is expensive is implementation details, and the
>> developer of PyPy should solve that instead of adding a clutch to the
>> stdlib.
> 
> A "clutch"? Even ignoring PyPy, an identitydict is still a useful primitive.

it may be useful, but if you can emulate it relatively easily with
regular dict, why bother with a new type?