.. _py-graph/GraphInterface:

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graph/GraphInterface
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.. default-domain:: py

.. py:currentmodule:: mod
.. cpp:namespace:: mod


Class ``GraphVertex``
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.. py:class:: GraphVertex

    A descriptor of either a vertex in a graph, or a null vertex.

    .. py:function:: __init__(self)

        Constructs a null descriptor.
    .. py::method:: __bool__(self)

        :returns: ``not isNull()``
        :rtype: bool
    .. py:method:: isNull()

        :returns: whether this is a null descriptor or not.
        :rtype: bool
    .. py:attribute:: id

        (Read-only) The index of the vertex. It will be in the range :math:`[0, numVertices[`.

        :type: int
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: graph

        (Read-only) The graph the vertex belongs to.

        :type: Graph
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: degree

        (Read-only) The degree of the vertex.

        :type: int
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: incidentEdges

        (Read-only) A range of incident edges to this vertex.

        :type: GraphIncidentEdgeRange
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: stringLabel

        (Read-only) The string label of the vertex.

        :type: str
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: atomId

        (Read-only) The atom id of the vertex.

        :type: AtomId
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: isotope

        (Read-only) The isotope of the vertex.

        :type: Isotope
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: charge

        (Read-only) The charge of the vertex.

        :type: Charge
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: radical

        (Read-only) The radical status of the vertex.

        :type: bool
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:method:: printStereo()
                 printStereo(p)

        Print the stereo configuration for the vertex.

        :param GraphPrinter p: the printing options used for the depiction.
        :returns: the name of the PDF-file that will be compiled in post-processing.
        :rtype: str
        :raises: :py:class:`LogicError` if it is a null descriptor.

Class ``GraphEdge``
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.. py:class:: GraphEdge

    A descriptor of either an edge in a graph, or a null edge.

    .. py:function:: __init__(self)

        Constructs a null descriptor.
    .. py::method:: __bool__(self)

        :returns: ``not isNull()``
        :rtype: bool
    .. py:method:: isNull()

        :returns: whether this is a null descriptor or not.
        :rtype: bool
    .. py:attribute:: graph

        (Read-only) The graph the edge belongs to.

        :type: Graph
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: source

        (Read-only) The source vertex of the edge.

        :type: GraphVertex
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. attribute:: target

        (Read-only) The target vertex of the edge.

        :type: GraphVertex
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: stringLabel

        (Read-only) The string label of the edge.

        :type: str
        :raises: :py:class:`LogicError` if it is a null descriptor.
    .. py:attribute:: bondType

        (Read-only) The bond type of the edge.

        :type: BondType
        :raises: :py:class:`LogicError` if it is a null descriptor.