Struct Query 

pub struct Query<'w, T: Component> { /* private fields */ }

Shared read access to all entities with component T.

Implementations

impl<'w, T: Component> Query<'w, T>

pub fn iter(&self) -> impl Iterator<Item = (Entity, &T)>

Iterate over matching (Entity, &T) pairs.

pub fn is_empty(&self) -> bool

Returns true if no entities matched.

pub fn len(&self) -> usize

Returns the number of matching entities.

Trait Implementations

impl<T: Component> SystemParam for Query<'_, T>

type Item<'w> = Query<'w, T>

The concrete type produced for a given world lifetime.

fn access() -> Vec<Access>

Declare what world data this parameter accesses.

unsafe fn fetch<'w>(world: UnsafeWorldCell) -> Query<'w, T>

Extract the parameter from the world.