How do I access all entities with a certain component? about specs HOT 5 CLOSED

fn run(&mut self, (transform, mut rigidbody, ball, paddle): Self::SystemData) {
    for (e_transform, e_rigidbody, e_ball) in (&transform, &mut rigidbody, &ball).join() {
        if is_key_pressed(KeyCode::Space)
        && e_rigidbody.velocity == Vec2::ZERO {
            e_rigidbody.velocity = vec2(e_ball.move_speed, -e_ball.move_speed);
        }

        if e_transform.position.x < 0.0
        || e_transform.position.x > SCREEN_WIDTH as f32 - 13.0 {
            e_rigidbody.velocity.x *= -1.0;
        }

        if e_transform.position.y < 0.0 {
            e_rigidbody.velocity.y *= -1.0;
        }

        for (p_transform, _p_paddle) in (&transform, &paddle).join() {
            if e_transform.position.y + 13.0 > p_transform.position.y
            && e_transform.position.x + 13.0 > p_transform.position.x
            && e_transform.position.x < p_transform.position.x + 80.0
            && e_rigidbody.velocity.y > 0.0 {
                e_rigidbody.velocity.y *= -1.0;
            }
        }
    }
}