14.5.6 Creating a Subgraph

PGX provides the following methods for creating subgraphs via a filter (see Filter Expressions for more information) expression:

• Java
• Python

PgxGraph filter(GraphFilter graphFilter)
PgxGraph filter(GraphFilter graphFilter, String newGraphName)
PgxGraph filter(Collection<VertexProperty<?, ?>> vertexProps, Collection<EdgeProperty<?>> edgeProps, GraphFilter graphFilter, String newGraphName)

filter(self, graph_filter, vertex_properties=True, edge_properties=True, name=None)

As in the other graph mutating methods, the user has the option to specify the name of the subgraph with the newGraphName parameter and of choosing the vertex and edge properties to be copied into the subgraph (vertexProps and edgeProps). All of the preceding methods return a PgxGraph object which represents the created subgraph.

All filter methods require a GraphFilter argument containing a filter expression. Fundamentally, the filter expression is a Boolean expression that is evaluated for every vertex and edge in the original graph (in parallel). If the expression is evaluated as true for the vertex or edge, then that vertex or edge is included in the subgraph.

See Creating Subgraphs for more information on how to create subgraphs from graphs loaded into memory.