cugraph.experimental.PropertyGraph.select_vertices#

PropertyGraph.select_vertices(expr, from_previous_selection=None)[source]#

Evaluate expr and return a PropertySelection object representing the vertices that match the expression.

Parameters:

exprstring: A python expression using property names and operators to select specific vertices.
from_previous_selectionPropertySelection, optional: A PropertySelection instance returned from a prior call to select_vertices() that can be used to select a subset of vertices to evaluate the expression against. This allows for a selection of the intersection of vertices of multiple types (eg. all vertices that are both type A and type B)

Returns:

PropertySelection: used for calls to extract_subgraph() in order to construct a Graph containing only specific vertices.

Examples

>>> import cugraph
>>> import cudf
>>> from cugraph.experimental import PropertyGraph
>>> df = cudf.DataFrame(columns=["src", "dst", "some_property"],
...                     data=[(99, 22, "a"),
...                           (98, 34, "b"),
...                           (97, 56, "c"),
...                           (96, 88, "d"),
...                          ])
>>> pG = PropertyGraph()
>>> pG.add_edge_data(df, type_name="etype", vertex_col_names=("src", "dst"))
>>> vert_df = cudf.DataFrame({"vert_id": [99, 22, 98, 34, 97, 56, 96, 88],
...                           "v_prop": [1, 2, 3, 4, 5, 6, 7, 8]})
>>> pG.add_vertex_data(vert_df, type_name="vtype", vertex_col_name="vert_id")
>>> selection = pG.select_vertices("(_TYPE_ == 'vtype') & (v_prop > 4)")
>>> G = pG.extract_subgraph(selection=selection)
>>> print (G.number_of_vertices())
4