Chris Angelico <ros...@gmail.com>: > On Wed, Aug 9, 2017 at 8:38 PM, Marko Rauhamaa <ma...@pacujo.net> wrote: >> Chris Angelico <ros...@gmail.com>: >> >>> On Wed, Aug 9, 2017 at 7:51 PM, Marko Rauhamaa <ma...@pacujo.net> wrote: >>>> Mutable objects can be used as keys into a dictionary. >>> >>> Only when the objects' mutability does not affect their values. >> >> Up to equality. The objects can carry all kinds of mutable payload as >> long as __hash__() and __eq__() don't change with it. > > Which means that its value won't change. That's what I said. Two > things will be equal regardless of that metadata.
In relational-database terms, your "value" is the primary key and your "metadata" is the rest of the columns. >> And Python doesn't enforce this in any way except for lists. That's >> somewhat unfortunate since sometimes you really would like an >> immutable (or rather, no-longer-mutable) list to act as a key. > > Then make a tuple out of it. Job done. You're trying to say that its > value won't now change. Yeah, when there's a will, there's a way. Marko -- https://mail.python.org/mailman/listinfo/python-list
