Undocumented

Function | `_add` |
Adds a single edge to the graph. |

Function | `_add` |
Adds some edges to the graph. |

Function | `_add` |
Adds a single vertex to the graph. Keyword arguments will be assigned as vertex attributes. Note that name as a keyword argument is treated specially; if a graph has name as a vertex attribute, it allows one to refer to vertices by their names in most places where igraph expects a vertex ID. |

Function | `_add` |
Adds some vertices to the graph. |

Function | `_as` |
Returns a directed copy of this graph. Arguments are passed on to `GraphBase.to_directed()` that is invoked on the copy. |

Function | `_as` |
Returns an undirected copy of this graph. Arguments are passed on to `GraphBase.to_undirected()` that is invoked on the copy. |

Function | `_clear` |
Clears the graph, deleting all vertices, edges, and attributes. |

Function | `_delete` |
Deletes some edges from the graph. |

Adds a single edge to the graph.

Keyword arguments (except the source and target arguments) will be assigned to the edge as attributes.

The performance cost of adding a single edge or several edges to a graph is similar. Thus, when adding several edges, a single `add_edges()` call is more efficient than multiple `add_edge()` calls.

Parameters | |

graph | Undocumented |

source | the source vertex of the edge or its name. |

target | the target vertex of the edge or its name. |

**kwds | Undocumented |

Returns | |

the newly added edge as an `Edge` object. Use add_edges([(source, target)]) if you don't need the `Edge` object and want to avoid the overhead of creating it. |

Adds some edges to the graph.

Parameters | |

graph | Undocumented |

es | the list of edges to be added. Every edge is represented with a tuple containing the vertex IDs or names of the two endpoints. Vertices are enumerated from zero. |

attributes | dict of sequences, all of length equal to the number of edges to be added, containing the attributes of the new edges. |

Adds a single vertex to the graph. Keyword arguments will be assigned as vertex attributes. Note that `name` as a keyword argument is treated specially; if a graph has `name` as a vertex attribute, it allows one to refer to vertices by their names in most places where igraph expects a vertex ID.

Returns | |

the newly added vertex as a `Vertex` object. Use add_vertices(1) if you don't need the `Vertex` object and want to avoid the overhead of creating t. |

Adds some vertices to the graph.

Note that if `n` is a sequence of strings, indicating the names of the new vertices, and attributes has a key `name`, the two conflict. In that case the attribute will be applied.

Parameters | |

graph | Undocumented |

n | the number of vertices to be added, or the name of a single vertex to be added, or a sequence of strings, each corresponding to the name of a vertex to be added. Names will be assigned to the name vertex attribute. |

attributes | dict of sequences, all of length equal to the number of vertices to be added, containing the attributes of the new vertices. If n is a string (so a single vertex is added), then the values of this dict are the attributes themselves, but if n=1 then they have to be lists of length 1. |

Returns a directed copy of this graph. Arguments are passed on to `GraphBase.to_directed()`

that is invoked on the copy.

Returns an undirected copy of this graph. Arguments are passed on to `GraphBase.to_undirected()`

that is invoked on the copy.

Clears the graph, deleting all vertices, edges, and attributes.

See Also | |

`GraphBase.delete_vertices` and `Graph.delete_edges` . |

Deletes some edges from the graph.

The set of edges to be deleted is determined by the positional and keyword arguments. If the function is called without any arguments, all edges are deleted. If any keyword argument is present, or the first positional argument is callable, an edge sequence is derived by calling `EdgeSeq.select`

with the same positional and keyword arguments. Edges in the derived edge sequence will be removed. Otherwise the first positional argument is considered as follows:

`None`- deletes all edges (deprecated since 0.8.3)- a single integer - deletes the edge with the given ID
- a list of integers - deletes the edges denoted by the given IDs
- a list of 2-tuples - deletes the edges denoted by the given source-target vertex pairs. When multiple edges are present between a given source-target vertex pair, only one is removed.

Unknown Field: deprecated | |

delete_edges(None) has been replaced by delete_edges() - with no arguments - since igraph 0.8.3. |