I have an owned object, and I want to move it into a hash set, but also get an immutable reference to that item in the hash set.
This seems like a perfect use case for the get_or_insert function, but this is apparently only experimental, and I would like to keep my codebase on the stable branch if possible.
I wish I could just insert the item, and then call .get(ITEM).unwrap() but I can't because the item has been moved into the hashset.
Is there a way of doing this that I'm not thinking of?
#Insert item into hash set and get reference to it
bleak urchin
gilded robin
entry and or_insert
my bad, thought you were talking about hashmap
Yeah that seems like it should be possible but isn't. Kinda weird.
I think the simplest solution is to add hashbrown as a dependency and use that get_or_insert. It's the same as std's but you don't need nightly.
bleak urchin
I think the simplest solution is to add hashbrown as a dependency and use that `...
Interesting I didn't know about that
Looks like it also brings performance improvements, I might switch to that outright
gilded robin
It's the same. It's what the std library uses.
random apex
Yeah that seems like it should be possible but isn't. Kinda weird.
Technically it is, but you have to manually match on the entry
match map.entry(key) {
Entry::Vacant(v) => v.insert(value),
Entry::Occupied(o) => o.into_mut(),
}
Oh wait
bleak urchin
It's the same. It's what the std library uses.
it claims on the github to be 2x faster than the standard library implementation
short aurora
bleak urchin
Oh I see so the rust standard library uses hashbrown now, and its 2x faster than what the standard library used to use
That makes sense
gilded robin
Oh and hashbrown::HashSet has entry!
random apex
Hashbrown is basically "hey, I would like all of the cool APIs std doesn't yet have thanks"
bleak urchin
Gotcha
gilded robin
... but or_insert doesn't return a reference to it.