Returns a Boolean value indicating whether the unit is null.
- iOS 8.0+
- Mac Catalyst 13.0+
- watchOS 2.0+
YES if the unit is null; otherwise,
Null units occur only when you create compound units in which all the units cancel out. For example, if you tried to create a unit by dividing deciliters by liters (
d), you would end up with a null unit.