AttributeParity filters features on the ODD/EVEN basis of a chosen numeric attribute.

Non-numeric features are output through a NAN (Not A Number) port. A _parity attribute is added to each feature with a value of either ODD, EVEN or NAN. Transformer and demo workspace attached below.

NB: The NAN port is for features whose values are not numeric. Technically, this differs from other FME NAN tests, which test whether the value of an attribute is literally "NAN".