pyflink.datastream.functions.KeySelector#
- class KeySelector[source]#
The KeySelector allows to use deterministic objects for operations such as reduce, reduceGroup, join coGroup, etc. If invoked multiple times on the same object, the returned key must be the same. The extractor takes an object an returns the deterministic key for that object.
Methods
close()get_key(value)User-defined function that deterministically extracts the key from an object.
open(runtime_context)