Universe Selection

var symbols = new [] {QuantConnect.Symbol.Create("SPY", SecurityType.Equity, Market.USA)};
AddUniverseSelection(new ManualUniverseSelectionModel(symbols));

# Adds a universe selection model to the algorithm, manually defining the set of securities to include in the algorithm.
symbols = [Symbol.create("SPY", SecurityType.EQUITY, Market.USA)]
self.add_universe_selection(ManualUniverseSelectionModel(symbols))

// Configures asynchronous universe settings for faster updates and includes both manual and EMA cross universe selection models for dynamic and static selection.
UniverseSettings.Asynchronous = true;
var symbols = new [] {QuantConnect.Symbol.Create("SPY", SecurityType.Equity, Market.USA)};
AddUniverseSelection(new ManualUniverseSelectionModel(symbols));

AddUniverseSelection(new EmaCrossUniverseSelectionModel());

# Configures asynchronous universe settings for faster updates and includes both manual and EMA cross universe selection models for dynamic and static selection.
self.universe_settings.asynchronous = True
symbols = [Symbol.create("SPY", SecurityType.EQUITY, Market.USA)]
self.add_universe_selection(ManualUniverseSelectionModel(symbols))
		
self.add_universe_selection(EmaCrossUniverseSelectionModel())

// Extend UniverseSelectionModel to define a custom security universe tailored to the algorithm.
public class MyUniverseSelectionModel : UniverseSelectionModel
{
    // Creates the universes for this algorithm
    public override IEnumerable<Universe> CreateUniverses(QCAlgorithm algorithm)
    {
        return new List<Universe>();
    }

    // Gets the next time the framework should invoke the `CreateUniverses` method to refresh the set of universes.
    public override DateTime GetNextRefreshTimeUtc()
    {
        return DateTime.MaxValue;
    }
}

# Extend UniverseSelectionModel to define a custom security universe tailored to the algorithm.
class MyUniverseSelectionModel(UniverseSelectionModel):

    # Creates the universes for this algorithm
    def create_universes(self, algorithm: QCAlgorithm) -> List[Universe]:
        universes = []
        return universes
    
    # Gets the next time the framework should invoke the `CreateUniverses` method to refresh the set of universes.
    def get_next_refresh_time_utc(self):
        return datetime.max

// Log added and removed securities to update the universe and adapt the strategy.
public override void OnSecuritiesChanged(QCAlgorithm algorithm, SecurityChanges changes)
{
    foreach (var security in changes.AddedSecurities)
    {
        Log($"Added {security.Symbol}");
    }

    foreach (var security in changes.RemovedSecurities)
    {
        Log($"Removed {security.Symbol}");
    }
}

# Log added and removed securities to update the universe and adapt the strategy.
def on_securities_changed(self, algorithm: QCAlgorithm, changes: SecurityChanges) -> None:
    for security in changes.added_securities::
        self.log(f"Added {security.symbol}")

    for security in changes.removed_securities:
        self.log(f"Removed {security.symbol}")