Struct Query 

pub struct Query<'a, Q: Query> { /* private fields */ }

Fetches components matching Q from every entity that has them. Include Entity in Q to get entity IDs back out of iteration.

Implementations

impl<'a, Q: Query> Query<'a, Q>

pub fn iter(&mut self) -> impl Iterator<Item = Q::Item<'_>>

Iterates every matching entity’s components.

pub fn get(&mut self, entity: Entity) -> Option<Q::Item<'_>>

Fetches one known entity directly, without scanning the rest of the query. None if it doesn’t exist or doesn’t match Q.

pub fn with<R: Query>(self) -> Query<'a, With<Q, R>>

Narrows to entities that also have component(s) R, without R joining the yielded items. Chainable with .without::<S>().

pub fn without<R: Query>(self) -> Query<'a, Without<Q, R>>

Narrows to entities that don’t have component(s) R.

pub fn single(&mut self) -> Q::Item<'_>

Expects exactly one matching entity (the player, the active camera). Panics otherwise — use get_single if that’s not guaranteed.

pub fn get_single(&mut self) -> Option<Q::Item<'_>>

Same as single, but None instead of panicking when there isn’t exactly one match.

Trait Implementations

impl<'a, Q: Query> IntoIterator for &'a mut Query<'a, Q>

type Item = <Q as Query>::Item<'a>

The type of the elements being iterated over.

type IntoIter = QueryIter<'a, Q>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<Q> SystemParam for Query<'static, Q>

where Q: Query + 'static,

type Item<'a> = Query<'a, Q>

The value actually handed to the system function.

type State = ()

Per-system persistent state (e.g. Local’s stored value) — () for anything stateless.

fn fetch<'a>( world: &'a World, _resources: &'a Resources, _state: &'a mut Self::State, ) -> Self::Item<'a>