We have project to use PGX to create our community graph, and to move forward i do not know how to use filter expression inside config json file. Point me a direction and i will lookup by myself.
Sorry for the long delay in the reply.
Did you look at the filter expression documentation? https://docs.oracle.com/cd/E56133_01/latest/reference/filter.html
Do you refer to the subgraph loading feature? https://docs.oracle.com/cd/E56133_01/latest/reference/loader/graph-config/subgraph.html