ChainMap is one of my favourites. I like when I find a use for it. The obvious one is cascading options type thing (like cmdline options -> env -> defaults). I also found a use for it recently when changing the underlying storage layer of a class without breaking the API.
My other favourite parts of the stdlib are functools and itertools. They are both full of stuff that gives you superpowers. I always find it a shame when I see developers do an ad hoc reimplantation of something in functools/itertools.
My other favourite parts of the stdlib are functools and itertools. They are both full of stuff that gives you superpowers. I always find it a shame when I see developers do an ad hoc reimplantation of something in functools/itertools.