<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>add_edge — NetworkX 1.8.1 documentation</title> <link rel="stylesheet" href="../../_static/networkx.css" type="text/css" /> <link rel="stylesheet" href="../../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../../', VERSION: '1.8.1', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: false }; </script> <script type="text/javascript" src="../../_static/jquery.js"></script> <script type="text/javascript" src="../../_static/underscore.js"></script> <script type="text/javascript" src="../../_static/doctools.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within NetworkX 1.8.1 documentation" href="../../_static/opensearch.xml"/> <link rel="top" title="NetworkX 1.8.1 documentation" href="../../index.html" /> <link rel="up" title="MultiDiGraph - Directed graphs with self loops and parallel edges" href="../classes.multidigraph.html" /> <link rel="next" title="add_edges_from" href="networkx.MultiDiGraph.add_edges_from.html" /> <link rel="prev" title="remove_nodes_from" href="networkx.MultiDiGraph.remove_nodes_from.html" /> </head> <body> <div style="color: black;background-color: white; font-size: 3.2em; text-align: left; padding: 15px 10px 10px 15px"> NetworkX </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../../genindex.html" title="General Index" accesskey="I">index</a></li> <li class="right" > <a href="../../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="networkx.MultiDiGraph.add_edges_from.html" title="add_edges_from" accesskey="N">next</a> |</li> <li class="right" > <a href="networkx.MultiDiGraph.remove_nodes_from.html" title="remove_nodes_from" accesskey="P">previous</a> |</li> <li><a href="http://networkx.github.com/">NetworkX Home </a> | </li> <li><a href="http://networkx.github.com/documentation.html">Documentation </a>| </li> <li><a href="http://networkx.github.com/download.html">Download </a> | </li> <li><a href="http://github.com/networkx">Developer (Github)</a></li> <li><a href="../index.html" >Reference</a> »</li> <li><a href="../pdf_reference.html" >Reference</a> »</li> <li><a href="../classes.html" >Graph types</a> »</li> <li><a href="../classes.multidigraph.html" accesskey="U">MultiDiGraph - Directed graphs with self loops and parallel edges</a> »</li> </ul> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <h4>Previous topic</h4> <p class="topless"><a href="networkx.MultiDiGraph.remove_nodes_from.html" title="previous chapter">remove_nodes_from</a></p> <h4>Next topic</h4> <p class="topless"><a href="networkx.MultiDiGraph.add_edges_from.html" title="next chapter">add_edges_from</a></p> <div id="searchbox" style="display: none"> <h3>Quick search</h3> <form class="search" action="../../search.html" method="get"> <input type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="add-edge"> <h1>add_edge<a class="headerlink" href="#add-edge" title="Permalink to this headline">¶</a></h1> <dl class="method"> <dt id="networkx.MultiDiGraph.add_edge"> <tt class="descclassname">MultiDiGraph.</tt><tt class="descname">add_edge</tt><big>(</big><em>u</em>, <em>v</em>, <em>key=None</em>, <em>attr_dict=None</em>, <em>**attr</em><big>)</big><a class="headerlink" href="#networkx.MultiDiGraph.add_edge" title="Permalink to this definition">¶</a></dt> <dd><p>Add an edge between u and v.</p> <p>The nodes u and v will be automatically added if they are not already in the graph.</p> <p>Edge attributes can be specified with keywords or by providing a dictionary with key/value pairs. See examples below.</p> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field-odd field"><th class="field-name">Parameters :</th><td class="field-body"><p class="first"><strong>u,v</strong> : nodes</p> <blockquote> <div><p>Nodes can be, for example, strings or numbers. Nodes must be hashable (and not None) Python objects.</p> </div></blockquote> <p><strong>key</strong> : hashable identifier, optional (default=lowest unused integer)</p> <blockquote> <div><p>Used to distinguish multiedges between a pair of nodes.</p> </div></blockquote> <p><strong>attr_dict</strong> : dictionary, optional (default= no attributes)</p> <blockquote> <div><p>Dictionary of edge attributes. Key/value pairs will update existing data associated with the edge.</p> </div></blockquote> <p><strong>attr</strong> : keyword arguments, optional</p> <blockquote class="last"> <div><p>Edge data (or labels or objects) can be assigned using keyword arguments.</p> </div></blockquote> </td> </tr> </tbody> </table> <div class="admonition-see-also admonition seealso"> <p class="first admonition-title">See also</p> <dl class="last docutils"> <dt><a class="reference internal" href="networkx.MultiDiGraph.add_edges_from.html#networkx.MultiDiGraph.add_edges_from" title="networkx.MultiDiGraph.add_edges_from"><tt class="xref py py-obj docutils literal"><span class="pre">add_edges_from</span></tt></a></dt> <dd>add a collection of edges</dd> </dl> </div> <p class="rubric">Notes</p> <p>To replace/update edge data, use the optional key argument to identify a unique edge. Otherwise a new edge will be created.</p> <p>NetworkX algorithms designed for weighted graphs cannot use multigraphs directly because it is not clear how to handle multiedge weights. Convert to Graph using edge attribute ‘weight’ to enable weighted graph algorithms.</p> <p class="rubric">Examples</p> <p>The following all add the edge e=(1,2) to graph G:</p> <div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">G</span> <span class="o">=</span> <span class="n">nx</span><span class="o">.</span><span class="n">MultiDiGraph</span><span class="p">()</span> <span class="gp">>>> </span><span class="n">e</span> <span class="o">=</span> <span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">)</span> <span class="gp">>>> </span><span class="n">G</span><span class="o">.</span><span class="n">add_edge</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span> <span class="c"># explicit two-node form</span> <span class="gp">>>> </span><span class="n">G</span><span class="o">.</span><span class="n">add_edge</span><span class="p">(</span><span class="o">*</span><span class="n">e</span><span class="p">)</span> <span class="c"># single edge as tuple of two nodes</span> <span class="gp">>>> </span><span class="n">G</span><span class="o">.</span><span class="n">add_edges_from</span><span class="p">(</span> <span class="p">[(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">)]</span> <span class="p">)</span> <span class="c"># add edges from iterable container</span> </pre></div> </div> <p>Associate data to edges using keywords:</p> <div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">G</span><span class="o">.</span><span class="n">add_edge</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="n">weight</span><span class="o">=</span><span class="mi">3</span><span class="p">)</span> <span class="gp">>>> </span><span class="n">G</span><span class="o">.</span><span class="n">add_edge</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="n">key</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">weight</span><span class="o">=</span><span class="mi">4</span><span class="p">)</span> <span class="c"># update data for key=0</span> <span class="gp">>>> </span><span class="n">G</span><span class="o">.</span><span class="n">add_edge</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="n">weight</span><span class="o">=</span><span class="mi">7</span><span class="p">,</span> <span class="n">capacity</span><span class="o">=</span><span class="mi">15</span><span class="p">,</span> <span class="n">length</span><span class="o">=</span><span class="mf">342.7</span><span class="p">)</span> </pre></div> </div> </dd></dl> </div> </div> </div> </div> <div class="clearer"></div> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../../genindex.html" title="General Index" >index</a></li> <li class="right" > <a href="../../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="networkx.MultiDiGraph.add_edges_from.html" title="add_edges_from" >next</a> |</li> <li class="right" > <a href="networkx.MultiDiGraph.remove_nodes_from.html" title="remove_nodes_from" >previous</a> |</li> <li><a href="http://networkx.github.com/">NetworkX Home </a> | </li> <li><a href="http://networkx.github.com/documentation.html">Documentation </a>| </li> <li><a href="http://networkx.github.com/download.html">Download </a> | </li> <li><a href="http://github.com/networkx">Developer (Github)</a></li> <li><a href="../index.html" >Reference</a> »</li> <li><a href="../pdf_reference.html" >Reference</a> »</li> <li><a href="../classes.html" >Graph types</a> »</li> <li><a href="../classes.multidigraph.html" >MultiDiGraph - Directed graphs with self loops and parallel edges</a> »</li> </ul> </div> <div class="footer"> © Copyright 2013, NetworkX Developers. 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