!=(_:_:)
Returns a Boolean value indicating whether the right-hand-side argument is not nil
.
static func != (lhs: _OptionalNilComparisonType, rhs: borrowing Wrapped?) -> Bool
Parameters
You can use this not-equal-to operator (!=
) to test whether an optional instance is not nil
even when the wrapped value’s type does not conform to the Equatable
protocol.
The following example declares the stream
variable as an optional instance of a hypothetical DataStream
type. Although DataStream
is not an Equatable
type, this operator allows checking whether stream
wraps a value and is therefore not nil
.
var stream: DataStream? = fetchDataStream()
if nil != stream {
print("The data stream has been configured.")
}
// Prints "The data stream has been configured."