# Source code for graph_tool.util

```#! /usr/bin/env python
# -*- coding: utf-8 -*-
#
# graph_tool -- a general graph manipulation python module
#
# Copyright (C) 2006-2021 Tiago de Paula Peixoto <tiago@skewed.de>
#
# This program is free software; you can redistribute it and/or modify it under
# Software Foundation; either version 3 of the License, or (at your option) any
# later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

"""
``graph_tool.util`` - Graph utilities
-------------------------------------

Summary
+++++++

.. autosummary::
:nosignatures:

find_vertex
find_vertex_range
find_edge
find_edge_range

Contents
++++++++
"""

from .. dl_import import dl_import
dl_import("from . import libgraph_tool_util")

from .. import _degree, _prop, _converter

__all__ = ["find_vertex", "find_vertex_range", "find_edge", "find_edge_range"]

[docs]def find_vertex(g, prop, match):
"""Find all vertices `v` for which `prop[v] = match`. The parameter prop
can be either a :class:`~graph_tool.VertexPropertyMap` or string with value "in",
"out" or "total", representing a degree type."""
if prop in ["in", "out", "total"]:
val = int(match)
else:
val = _converter(prop.value_type())(match)
ret = libgraph_tool_util.\
find_vertex_range(g._Graph__graph, _degree(g, prop),
(val, val))
return ret

[docs]def find_vertex_range(g, prop, range):
"""Find all vertices `v` for which `range <= prop[v] <= range`. The
parameter prop can be either a :class:`~graph_tool.VertexPropertyMap` or string
with value "in", "out" or "total", representing a degree type."""
if prop in ["in", "out", "total"]:
convert = lambda x: int(x)
else:
convert = _converter(prop.value_type())
ret = libgraph_tool_util.\
find_vertex_range(g._Graph__graph, _degree(g, prop),
(convert(range), convert(range)))
return ret

[docs]def find_edge(g, prop, match):
"""Find all edges `e` for which `prop[e] = match`. The parameter prop
must be a :class:`~graph_tool.EdgePropertyMap`."""
val = _converter(prop.value_type())(match)
ret = libgraph_tool_util.\
find_edge_range(g._Graph__graph, _prop("e", g, prop),
(val, val))
return ret

[docs]def find_edge_range(g, prop, range):
"""Find all edges `e` for which `range <= prop[e] <= range`. The
parameter prop can be either a :class:`~graph_tool.EdgePropertyMap`."""
convert = _converter(prop.value_type())
ret = libgraph_tool_util.\
find_edge_range(g._Graph__graph, _prop("e", g, prop),
(convert(range), convert(range)))
return ret
```