Struct View

pub struct View<'q, Q>
where
    Q: Query,
{ /* private fields */ }

Provides random access to the results of a query

Implementations

impl<'q, Q> View<'q, Q>

where Q: Query,

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

where Q: QueryShared,

Retrieve the query results corresponding to entity

Will yield None if the entity does not exist or does not match the query.

Does not require exclusive access to the map, but is defined only for queries yielding only shared references.

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

Retrieve the query results corresponding to entity

Will yield None if the entity does not exist or does not match the query.

pub fn contains(&self, entity: Entity) -> bool

Equivalent to get(entity).is_some(), but does not require Q: QueryShared

pub unsafe fn get_unchecked( &self, entity: Entity, ) -> Option<<Q as Query>::Item<'_>>

Like get_mut, but allows simultaneous access to multiple entities

Safety

Must not be invoked while any unique borrow of the fetched components of entity is live.

pub fn get_many_mut<const N: usize>( &mut self, entities: [Entity; N], ) -> [Option<<Q as Query>::Item<'_>>; N]

Like get_mut, but allows checked simultaneous access to multiple entities

For N > 3, the check for distinct entities will clone the array and take O(N log N) time.

Examples

let mut world = World::new();

let a = world.spawn((1, 1.0));
let b = world.spawn((2, 4.0));
let c = world.spawn((3, 9.0));

let mut query = world.query_mut::<&mut i32>();
let mut view = query.view();
let [a,b,c] = view.get_mut_n([a, b, c]);

assert_eq!(*a.unwrap(), 1);
assert_eq!(*b.unwrap(), 2);
assert_eq!(*c.unwrap(), 3);

pub fn iter_mut(&mut self) -> ViewIter<'_, Q>

Iterate over all entities satisfying Q

Equivalent to QueryBorrow::iter.

Trait Implementations

impl<'a, 'q, Q> IntoIterator for &'a mut View<'q, Q>

where Q: Query,

type IntoIter = ViewIter<'a, Q>

Which kind of iterator are we turning this into?

type Item = (Entity, <Q as Query>::Item<'a>)

The type of the elements being iterated over.

fn into_iter(self) -> <&'a mut View<'q, Q> as IntoIterator>::IntoIter

Creates an iterator from a value.

impl<'q, Q> Send for View<'q, Q>

where Q: Query, <Q as Query>::Item<'a>: for<'a> Send,

impl<'q, Q> Sync for View<'q, Q>

where Q: Query, <Q as Query>::Item<'a>: for<'a> Send,