14.10.5.6 Combining Filter Expressions

Any filter expression used for subgraph filtering, can be combined with any other filter expression to form a new filter expression.

Filters can be combined using the following operations:

• intersection
• union

The intersection of two filters will only keep a vertex or edge, if both filters would accept it.

Note:

The intersection of two filters will not behave as an AND in the filter expression.

The union of two filters will keep a vertex or edge, if one of the filters would accept it.

Note:

The union of filters will not behave as an OR in the filter expression.

In the following example an edge filter is intersected with a vertex filter. The resulting subgraph will only include vertices that have the name 'PGX' and will only include edges that have a cost greater than 5.

• JShell
• Java
• Python

opg4j> var edgeFilter = EdgeFilter.fromExpression("edge.cost > 5")
opg4j> var vertexFilter = VertexFilter.fromExpression("vertex.name = 'PGX'")
opg4j> var combinedFilter = edgeFilter.intersect(vertexFilter)

EdgeFilter edgeFilter = EdgeFilter.fromExpression("edge.cost > 5");
VertexFilter vertexFilter = VertexFilter.fromExpression("vertex.name = 'PGX'");
GraphFilter combinedFilter = edgeFilter.intersect(vertexFilter);

edge_filter = EdgeFilter("edge.cost > 5")
vertex_filter = VertexFilter("vertex.name = 'PGX'")
combined_filter = edge_filter.intersect(vertex_filter)

In contrast, the subgraph created by the union of those filters will include vertices that either have the name 'PGX' or that has an incoming or outgoing edge with a cost greater than 5. It will also include edges with a cost greater than 5, as well as edges for which the source and destination vertex have the name 'PGX'.