# -*- coding: utf-8 -*-
"""Filter functions for edges in BEL graphs.
A edge predicate is a function that takes five arguments: a :class:`BELGraph`, a source node, a target node, a key,
and a data dictionary. It returns a boolean representing whether the edge passed the given test.
This module contains a set of default functions for filtering lists of edges and building edge predicate functions.
A general use for an edge predicate is to use the built-in :func:`filter` in code like
:code:`filter(your_edge_predicate, graph.edges(keys=True, data=True))`
"""
from typing import Iterable
from .typing import EdgeIterator, EdgePredicate, EdgePredicates
from ..graph import BELGraph
from ...dsl import BaseEntity
__all__ = [
"invert_edge_predicate",
"and_edge_predicates",
"filter_edges",
"count_passed_edge_filter",
]
[docs]def invert_edge_predicate(edge_predicate: EdgePredicate) -> EdgePredicate: # noqa: D202
"""Build an edge predicate that is the inverse of the given edge predicate."""
def _inverse_filter(graph, u, v, k):
return not edge_predicate(graph, u, v, k)
return _inverse_filter
[docs]def and_edge_predicates(edge_predicates: EdgePredicates) -> EdgePredicate:
"""Concatenate multiple edge predicates to a new predicate that requires all predicates to be met."""
# If something that isn't a list or tuple is given, assume it's a function and return it
if not isinstance(edge_predicates, Iterable):
return edge_predicates
edge_predicates = tuple(edge_predicates)
# If only one predicate is given, don't bother wrapping it
if 1 == len(edge_predicates):
return edge_predicates[0]
def concatenated_edge_predicate(graph: BELGraph, u: BaseEntity, v: BaseEntity, k: str) -> bool:
"""Pass only for an edge that pass all enclosed predicates.
:return: If the edge passes all enclosed predicates
"""
return all(edge_predicate(graph, u, v, k) for edge_predicate in edge_predicates)
return concatenated_edge_predicate
[docs]def filter_edges(graph: BELGraph, edge_predicates: EdgePredicates) -> EdgeIterator:
"""Apply a set of filters to the edges iterator of a BEL graph.
:return: An iterable of edges that pass all predicates
"""
compound_edge_predicate = and_edge_predicates(edge_predicates=edge_predicates)
for u, v, k in graph.edges(keys=True):
if compound_edge_predicate(graph, u, v, k):
yield u, v, k
[docs]def count_passed_edge_filter(graph: BELGraph, edge_predicates: EdgePredicates) -> int:
"""Return the number of edges passing a given set of predicates."""
return sum(1 for _ in filter_edges(graph, edge_predicates=edge_predicates))