C# yield

I’ve seen the “yield” keyword here and there… but I’ve never really cared to learn what it does. Until now. Actually, it’s my understanding that it’s more or less a convenience keyword like “var.”

In short, “yield” allows you to return an IEnumerable without creating a List.

Example: (old way)

IEnumerable<Car> FindBlueCars(){
	var blueCars = new List<Car>();
	foreach (var c in _allCars)
		if (c.IsBlue())
			blueCars.Add(c);
	return blueCars;
}

Example: (new way)

IEnumerable<Car> FindBlueCars(){
	foreach (var c in _allCars)
		if (c.IsBlue())
			yield return c;
}

Saves some typing. MSDN reference for yield.

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-JP