Struct Query 

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

Immutable query builder

Example

world.select::<(Position, Velocity)>()
    .tagged("player")
    .not_tagged("frozen")
    .each(|entity, (pos, vel)| {
        println!("{:?}", pos);
    });

Implementations

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

where T: QueryTuple<'w>,

pub fn tagged(self, tag: &str) -> Query<'w, T>

Require entities to have this tag

pub fn not_tagged(self, tag: &str) -> Query<'w, T>

Exclude entities with this tag

pub fn with<C>(self) -> Query<'w, T>

where C: Component,

Filters entities that have this component without fetching it

Useful when you need to check component existence but don’t need the data.

Example

// Find all entities with Health that also have Velocity
world.select::<(Health,)>()
    .with::<Velocity>()
    .each(|entity, (health,)| {
        println!("Fast entity: {}", health.0);
    });

pub fn without<C>(self) -> Query<'w, T>

where C: Component,

Filters entities that don’t have this component

Example

// Find all entities with Health but no Shield
world.select::<(Health,)>()
    .without::<Shield>()
    .each(|entity, (health,)| {
        println!("Vulnerable: {}", health.0);
    });

pub fn each<F>(self, f: F)

where F: FnMut(Entity, <T as QueryTuple<'w>>::Item),

Iterate over all matching entities