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<h1>Source code for networkx.algorithms.operators.binary</h1><div class="highlight"><pre>
<span class="sd">"""</span>
<span class="sd">Operations on graphs including union, intersection, difference.</span>
<span class="sd">"""</span>
<span class="c"># Copyright (C) 2004-2012 by</span>
<span class="c"># Aric Hagberg <hagberg@lanl.gov></span>
<span class="c"># Dan Schult <dschult@colgate.edu></span>
<span class="c"># Pieter Swart <swart@lanl.gov></span>
<span class="c"># All rights reserved.</span>
<span class="c"># BSD license.</span>
<span class="kn">import</span> <span class="nn">networkx</span> <span class="kn">as</span> <span class="nn">nx</span>
<span class="kn">from</span> <span class="nn">networkx.utils</span> <span class="kn">import</span> <span class="n">is_string_like</span>
<span class="n">__author__</span> <span class="o">=</span> <span class="s">"""</span><span class="se">\n</span><span class="s">"""</span><span class="o">.</span><span class="n">join</span><span class="p">([</span><span class="s">'Aric Hagberg (hagberg@lanl.gov)'</span><span class="p">,</span>
<span class="s">'Pieter Swart (swart@lanl.gov)'</span><span class="p">,</span>
<span class="s">'Dan Schult(dschult@colgate.edu)'</span><span class="p">])</span>
<span class="n">__all__</span> <span class="o">=</span> <span class="p">[</span><span class="s">'union'</span><span class="p">,</span> <span class="s">'compose'</span><span class="p">,</span> <span class="s">'disjoint_union'</span><span class="p">,</span> <span class="s">'intersection'</span><span class="p">,</span>
<span class="s">'difference'</span><span class="p">,</span> <span class="s">'symmetric_difference'</span><span class="p">]</span>
<div class="viewcode-block" id="union"><a class="viewcode-back" href="../../../../reference/generated/networkx.algorithms.operators.binary.union.html#networkx.algorithms.operators.binary.union">[docs]</a><span class="k">def</span> <span class="nf">union</span><span class="p">(</span><span class="n">G</span><span class="p">,</span> <span class="n">H</span><span class="p">,</span> <span class="n">rename</span><span class="o">=</span><span class="p">(</span><span class="bp">None</span><span class="p">,</span> <span class="bp">None</span><span class="p">),</span> <span class="n">name</span><span class="o">=</span><span class="bp">None</span><span class="p">):</span>
<span class="sd">""" Return the union of graphs G and H.</span>
<span class="sd"> Graphs G and H must be disjoint, otherwise an exception is raised.</span>
<span class="sd"> Parameters</span>
<span class="sd"> ----------</span>
<span class="sd"> G,H : graph</span>
<span class="sd"> A NetworkX graph</span>
<span class="sd"> create_using : NetworkX graph</span>
<span class="sd"> Use specified graph for result. Otherwise</span>
<span class="sd"> rename : bool , default=(None, None)</span>
<span class="sd"> Node names of G and H can be changed by specifying the tuple</span>
<span class="sd"> rename=('G-','H-') (for example). Node "u" in G is then renamed</span>
<span class="sd"> "G-u" and "v" in H is renamed "H-v".</span>
<span class="sd"> name : string</span>
<span class="sd"> Specify the name for the union graph</span>
<span class="sd"> Returns</span>
<span class="sd"> -------</span>
<span class="sd"> U : A union graph with the same type as G.</span>
<span class="sd"> Notes</span>
<span class="sd"> -----</span>
<span class="sd"> To force a disjoint union with node relabeling, use</span>
<span class="sd"> disjoint_union(G,H) or convert_node_labels_to integers().</span>
<span class="sd"> Graph, edge, and node attributes are propagated from G and H</span>
<span class="sd"> to the union graph. If a graph attribute is present in both</span>
<span class="sd"> G and H the value from H is used.</span>
<span class="sd"> See Also</span>
<span class="sd"> --------</span>
<span class="sd"> disjoint_union</span>
<span class="sd"> """</span>
<span class="c"># Union is the same type as G</span>
<span class="n">R</span> <span class="o">=</span> <span class="n">G</span><span class="o">.</span><span class="n">__class__</span><span class="p">()</span>
<span class="k">if</span> <span class="n">name</span> <span class="ow">is</span> <span class="bp">None</span><span class="p">:</span>
<span class="n">name</span> <span class="o">=</span> <span class="s">"union( </span><span class="si">%s</span><span class="s">, </span><span class="si">%s</span><span class="s"> )"</span><span class="o">%</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">name</span><span class="p">,</span><span class="n">H</span><span class="o">.</span><span class="n">name</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">name</span> <span class="o">=</span> <span class="n">name</span>
<span class="c"># rename graph to obtain disjoint node labels</span>
<span class="k">def</span> <span class="nf">add_prefix</span><span class="p">(</span><span class="n">graph</span><span class="p">,</span> <span class="n">prefix</span><span class="p">):</span>
<span class="k">if</span> <span class="n">prefix</span> <span class="ow">is</span> <span class="bp">None</span><span class="p">:</span>
<span class="k">return</span> <span class="n">graph</span>
<span class="k">def</span> <span class="nf">label</span><span class="p">(</span><span class="n">x</span><span class="p">):</span>
<span class="k">if</span> <span class="n">is_string_like</span><span class="p">(</span><span class="n">x</span><span class="p">):</span>
<span class="n">name</span><span class="o">=</span><span class="n">prefix</span><span class="o">+</span><span class="n">x</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">name</span><span class="o">=</span><span class="n">prefix</span><span class="o">+</span><span class="nb">repr</span><span class="p">(</span><span class="n">x</span><span class="p">)</span>
<span class="k">return</span> <span class="n">name</span>
<span class="k">return</span> <span class="n">nx</span><span class="o">.</span><span class="n">relabel_nodes</span><span class="p">(</span><span class="n">graph</span><span class="p">,</span> <span class="n">label</span><span class="p">)</span>
<span class="n">G</span> <span class="o">=</span> <span class="n">add_prefix</span><span class="p">(</span><span class="n">G</span><span class="p">,</span><span class="n">rename</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span>
<span class="n">H</span> <span class="o">=</span> <span class="n">add_prefix</span><span class="p">(</span><span class="n">H</span><span class="p">,</span><span class="n">rename</span><span class="p">[</span><span class="mi">1</span><span class="p">])</span>
<span class="k">if</span> <span class="nb">set</span><span class="p">(</span><span class="n">G</span><span class="p">)</span> <span class="o">&</span> <span class="nb">set</span><span class="p">(</span><span class="n">H</span><span class="p">):</span>
<span class="k">raise</span> <span class="n">nx</span><span class="o">.</span><span class="n">NetworkXError</span><span class="p">(</span><span class="s">'The node sets of G and H are not disjoint.'</span><span class="p">,</span>
<span class="s">'Use appropriate rename=(Gprefix,Hprefix)'</span>
<span class="s">'or use disjoint_union(G,H).'</span><span class="p">)</span>
<span class="k">if</span> <span class="n">G</span><span class="o">.</span><span class="n">is_multigraph</span><span class="p">():</span>
<span class="n">G_edges</span> <span class="o">=</span> <span class="n">G</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">keys</span><span class="o">=</span><span class="bp">True</span><span class="p">,</span> <span class="n">data</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">G_edges</span> <span class="o">=</span> <span class="n">G</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">data</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="k">if</span> <span class="n">H</span><span class="o">.</span><span class="n">is_multigraph</span><span class="p">():</span>
<span class="n">H_edges</span> <span class="o">=</span> <span class="n">H</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">keys</span><span class="o">=</span><span class="bp">True</span><span class="p">,</span> <span class="n">data</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">H_edges</span> <span class="o">=</span> <span class="n">H</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">data</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="c"># add nodes</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_nodes_from</span><span class="p">(</span><span class="n">G</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_edges_from</span><span class="p">(</span><span class="n">G_edges</span><span class="p">)</span>
<span class="c"># add edges</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_nodes_from</span><span class="p">(</span><span class="n">H</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_edges_from</span><span class="p">(</span><span class="n">H_edges</span><span class="p">)</span>
<span class="c"># add node attributes</span>
<span class="n">R</span><span class="o">.</span><span class="n">node</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">node</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">node</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">H</span><span class="o">.</span><span class="n">node</span><span class="p">)</span>
<span class="c"># add graph attributes, H attributes take precedent over G attributes</span>
<span class="n">R</span><span class="o">.</span><span class="n">graph</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">graph</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">graph</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">H</span><span class="o">.</span><span class="n">graph</span><span class="p">)</span>
<span class="k">return</span> <span class="n">R</span>
</div>
<div class="viewcode-block" id="disjoint_union"><a class="viewcode-back" href="../../../../reference/generated/networkx.algorithms.operators.binary.disjoint_union.html#networkx.algorithms.operators.binary.disjoint_union">[docs]</a><span class="k">def</span> <span class="nf">disjoint_union</span><span class="p">(</span><span class="n">G</span><span class="p">,</span><span class="n">H</span><span class="p">):</span>
<span class="sd">""" Return the disjoint union of graphs G and H.</span>
<span class="sd"> This algorithm forces distinct integer node labels.</span>
<span class="sd"> Parameters</span>
<span class="sd"> ----------</span>
<span class="sd"> G,H : graph</span>
<span class="sd"> A NetworkX graph</span>
<span class="sd"> Returns</span>
<span class="sd"> -------</span>
<span class="sd"> U : A union graph with the same type as G.</span>
<span class="sd"> Notes</span>
<span class="sd"> -----</span>
<span class="sd"> A new graph is created, of the same class as G. It is recommended</span>
<span class="sd"> that G and H be either both directed or both undirected.</span>
<span class="sd"> The nodes of G are relabeled 0 to len(G)-1, and the nodes of H are</span>
<span class="sd"> relabeled len(G) to len(G)+len(H)-1.</span>
<span class="sd"> Graph, edge, and node attributes are propagated from G and H</span>
<span class="sd"> to the union graph. If a graph attribute is present in both</span>
<span class="sd"> G and H the value from H is used.</span>
<span class="sd"> """</span>
<span class="n">R1</span><span class="o">=</span><span class="n">nx</span><span class="o">.</span><span class="n">convert_node_labels_to_integers</span><span class="p">(</span><span class="n">G</span><span class="p">)</span>
<span class="n">R2</span><span class="o">=</span><span class="n">nx</span><span class="o">.</span><span class="n">convert_node_labels_to_integers</span><span class="p">(</span><span class="n">H</span><span class="p">,</span><span class="n">first_label</span><span class="o">=</span><span class="nb">len</span><span class="p">(</span><span class="n">R1</span><span class="p">))</span>
<span class="n">R</span><span class="o">=</span><span class="n">union</span><span class="p">(</span><span class="n">R1</span><span class="p">,</span><span class="n">R2</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">name</span><span class="o">=</span><span class="s">"disjoint_union( </span><span class="si">%s</span><span class="s">, </span><span class="si">%s</span><span class="s"> )"</span><span class="o">%</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">name</span><span class="p">,</span><span class="n">H</span><span class="o">.</span><span class="n">name</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">graph</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">graph</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">graph</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">H</span><span class="o">.</span><span class="n">graph</span><span class="p">)</span>
<span class="k">return</span> <span class="n">R</span>
</div>
<div class="viewcode-block" id="intersection"><a class="viewcode-back" href="../../../../reference/generated/networkx.algorithms.operators.binary.intersection.html#networkx.algorithms.operators.binary.intersection">[docs]</a><span class="k">def</span> <span class="nf">intersection</span><span class="p">(</span><span class="n">G</span><span class="p">,</span> <span class="n">H</span><span class="p">):</span>
<span class="sd">"""Return a new graph that contains only the edges that exist in</span>
<span class="sd"> both G and H.</span>
<span class="sd"> The node sets of H and G must be the same.</span>
<span class="sd"> Parameters</span>
<span class="sd"> ----------</span>
<span class="sd"> G,H : graph</span>
<span class="sd"> A NetworkX graph. G and H must have the same node sets.</span>
<span class="sd"> Returns</span>
<span class="sd"> -------</span>
<span class="sd"> GH : A new graph with the same type as G.</span>
<span class="sd"> Notes</span>
<span class="sd"> -----</span>
<span class="sd"> Attributes from the graph, nodes, and edges are not copied to the new</span>
<span class="sd"> graph. If you want a new graph of the intersection of G and H</span>
<span class="sd"> with the attributes (including edge data) from G use remove_nodes_from()</span>
<span class="sd"> as follows</span>
<span class="sd"> >>> G=nx.path_graph(3)</span>
<span class="sd"> >>> H=nx.path_graph(5)</span>
<span class="sd"> >>> R=G.copy()</span>
<span class="sd"> >>> R.remove_nodes_from(n for n in G if n not in H)</span>
<span class="sd"> """</span>
<span class="c"># create new graph</span>
<span class="n">R</span><span class="o">=</span><span class="n">nx</span><span class="o">.</span><span class="n">create_empty_copy</span><span class="p">(</span><span class="n">G</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">name</span><span class="o">=</span><span class="s">"Intersection of (</span><span class="si">%s</span><span class="s"> and </span><span class="si">%s</span><span class="s">)"</span><span class="o">%</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">name</span><span class="p">,</span> <span class="n">H</span><span class="o">.</span><span class="n">name</span><span class="p">)</span>
<span class="k">if</span> <span class="nb">set</span><span class="p">(</span><span class="n">G</span><span class="p">)</span><span class="o">!=</span><span class="nb">set</span><span class="p">(</span><span class="n">H</span><span class="p">):</span>
<span class="k">raise</span> <span class="n">nx</span><span class="o">.</span><span class="n">NetworkXError</span><span class="p">(</span><span class="s">"Node sets of graphs are not equal"</span><span class="p">)</span>
<span class="k">if</span> <span class="n">G</span><span class="o">.</span><span class="n">number_of_edges</span><span class="p">()</span><span class="o"><=</span><span class="n">H</span><span class="o">.</span><span class="n">number_of_edges</span><span class="p">():</span>
<span class="k">if</span> <span class="n">G</span><span class="o">.</span><span class="n">is_multigraph</span><span class="p">():</span>
<span class="n">edges</span><span class="o">=</span><span class="n">G</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">keys</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">edges</span><span class="o">=</span><span class="n">G</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">()</span>
<span class="k">for</span> <span class="n">e</span> <span class="ow">in</span> <span class="n">edges</span><span class="p">:</span>
<span class="k">if</span> <span class="n">H</span><span class="o">.</span><span class="n">has_edge</span><span class="p">(</span><span class="o">*</span><span class="n">e</span><span class="p">):</span>
<span class="n">R</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="k">else</span><span class="p">:</span>
<span class="k">if</span> <span class="n">H</span><span class="o">.</span><span class="n">is_multigraph</span><span class="p">():</span>
<span class="n">edges</span><span class="o">=</span><span class="n">H</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">keys</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">edges</span><span class="o">=</span><span class="n">H</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">()</span>
<span class="k">for</span> <span class="n">e</span> <span class="ow">in</span> <span class="n">edges</span><span class="p">:</span>
<span class="k">if</span> <span class="n">G</span><span class="o">.</span><span class="n">has_edge</span><span class="p">(</span><span class="o">*</span><span class="n">e</span><span class="p">):</span>
<span class="n">R</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="k">return</span> <span class="n">R</span>
</div>
<div class="viewcode-block" id="difference"><a class="viewcode-back" href="../../../../reference/generated/networkx.algorithms.operators.binary.difference.html#networkx.algorithms.operators.binary.difference">[docs]</a><span class="k">def</span> <span class="nf">difference</span><span class="p">(</span><span class="n">G</span><span class="p">,</span> <span class="n">H</span><span class="p">):</span>
<span class="sd">"""Return a new graph that contains the edges that exist in G but not in H.</span>
<span class="sd"> The node sets of H and G must be the same.</span>
<span class="sd"> Parameters</span>
<span class="sd"> ----------</span>
<span class="sd"> G,H : graph</span>
<span class="sd"> A NetworkX graph. G and H must have the same node sets.</span>
<span class="sd"> Returns</span>
<span class="sd"> -------</span>
<span class="sd"> D : A new graph with the same type as G.</span>
<span class="sd"> Notes</span>
<span class="sd"> -----</span>
<span class="sd"> Attributes from the graph, nodes, and edges are not copied to the new</span>
<span class="sd"> graph. If you want a new graph of the difference of G and H with</span>
<span class="sd"> with the attributes (including edge data) from G use remove_nodes_from()</span>
<span class="sd"> as follows:</span>
<span class="sd"> >>> G=nx.path_graph(3)</span>
<span class="sd"> >>> H=nx.path_graph(5)</span>
<span class="sd"> >>> R=G.copy()</span>
<span class="sd"> >>> R.remove_nodes_from(n for n in G if n in H)</span>
<span class="sd"> """</span>
<span class="c"># create new graph</span>
<span class="n">R</span><span class="o">=</span><span class="n">nx</span><span class="o">.</span><span class="n">create_empty_copy</span><span class="p">(</span><span class="n">G</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">name</span><span class="o">=</span><span class="s">"Difference of (</span><span class="si">%s</span><span class="s"> and </span><span class="si">%s</span><span class="s">)"</span><span class="o">%</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">name</span><span class="p">,</span> <span class="n">H</span><span class="o">.</span><span class="n">name</span><span class="p">)</span>
<span class="k">if</span> <span class="nb">set</span><span class="p">(</span><span class="n">G</span><span class="p">)</span><span class="o">!=</span><span class="nb">set</span><span class="p">(</span><span class="n">H</span><span class="p">):</span>
<span class="k">raise</span> <span class="n">nx</span><span class="o">.</span><span class="n">NetworkXError</span><span class="p">(</span><span class="s">"Node sets of graphs not equal"</span><span class="p">)</span>
<span class="k">if</span> <span class="n">G</span><span class="o">.</span><span class="n">is_multigraph</span><span class="p">():</span>
<span class="n">edges</span><span class="o">=</span><span class="n">G</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">keys</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">edges</span><span class="o">=</span><span class="n">G</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">()</span>
<span class="k">for</span> <span class="n">e</span> <span class="ow">in</span> <span class="n">edges</span><span class="p">:</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">H</span><span class="o">.</span><span class="n">has_edge</span><span class="p">(</span><span class="o">*</span><span class="n">e</span><span class="p">):</span>
<span class="n">R</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="k">return</span> <span class="n">R</span>
</div>
<div class="viewcode-block" id="symmetric_difference"><a class="viewcode-back" href="../../../../reference/generated/networkx.algorithms.operators.binary.symmetric_difference.html#networkx.algorithms.operators.binary.symmetric_difference">[docs]</a><span class="k">def</span> <span class="nf">symmetric_difference</span><span class="p">(</span><span class="n">G</span><span class="p">,</span> <span class="n">H</span><span class="p">):</span>
<span class="sd">"""Return new graph with edges that exist in either G or H but not both.</span>
<span class="sd"> The node sets of H and G must be the same.</span>
<span class="sd"> Parameters</span>
<span class="sd"> ----------</span>
<span class="sd"> G,H : graph</span>
<span class="sd"> A NetworkX graph. G and H must have the same node sets.</span>
<span class="sd"> Returns</span>
<span class="sd"> -------</span>
<span class="sd"> D : A new graph with the same type as G.</span>
<span class="sd"> Notes</span>
<span class="sd"> -----</span>
<span class="sd"> Attributes from the graph, nodes, and edges are not copied to the new</span>
<span class="sd"> graph.</span>
<span class="sd"> """</span>
<span class="c"># create new graph</span>
<span class="n">R</span><span class="o">=</span><span class="n">nx</span><span class="o">.</span><span class="n">create_empty_copy</span><span class="p">(</span><span class="n">G</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">name</span><span class="o">=</span><span class="s">"Symmetric difference of (</span><span class="si">%s</span><span class="s"> and </span><span class="si">%s</span><span class="s">)"</span><span class="o">%</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">name</span><span class="p">,</span> <span class="n">H</span><span class="o">.</span><span class="n">name</span><span class="p">)</span>
<span class="k">if</span> <span class="nb">set</span><span class="p">(</span><span class="n">G</span><span class="p">)</span><span class="o">!=</span><span class="nb">set</span><span class="p">(</span><span class="n">H</span><span class="p">):</span>
<span class="k">raise</span> <span class="n">nx</span><span class="o">.</span><span class="n">NetworkXError</span><span class="p">(</span><span class="s">"Node sets of graphs not equal"</span><span class="p">)</span>
<span class="n">gnodes</span><span class="o">=</span><span class="nb">set</span><span class="p">(</span><span class="n">G</span><span class="p">)</span> <span class="c"># set of nodes in G</span>
<span class="n">hnodes</span><span class="o">=</span><span class="nb">set</span><span class="p">(</span><span class="n">H</span><span class="p">)</span> <span class="c"># set of nodes in H</span>
<span class="n">nodes</span><span class="o">=</span><span class="n">gnodes</span><span class="o">.</span><span class="n">symmetric_difference</span><span class="p">(</span><span class="n">hnodes</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_nodes_from</span><span class="p">(</span><span class="n">nodes</span><span class="p">)</span>
<span class="k">if</span> <span class="n">G</span><span class="o">.</span><span class="n">is_multigraph</span><span class="p">():</span>
<span class="n">edges</span><span class="o">=</span><span class="n">G</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">keys</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">edges</span><span class="o">=</span><span class="n">G</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">()</span>
<span class="c"># we could copy the data here but then this function doesn't</span>
<span class="c"># match intersection and difference</span>
<span class="k">for</span> <span class="n">e</span> <span class="ow">in</span> <span class="n">edges</span><span class="p">:</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">H</span><span class="o">.</span><span class="n">has_edge</span><span class="p">(</span><span class="o">*</span><span class="n">e</span><span class="p">):</span>
<span class="n">R</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="k">if</span> <span class="n">H</span><span class="o">.</span><span class="n">is_multigraph</span><span class="p">():</span>
<span class="n">edges</span><span class="o">=</span><span class="n">H</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">keys</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">edges</span><span class="o">=</span><span class="n">H</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">()</span>
<span class="k">for</span> <span class="n">e</span> <span class="ow">in</span> <span class="n">edges</span><span class="p">:</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">G</span><span class="o">.</span><span class="n">has_edge</span><span class="p">(</span><span class="o">*</span><span class="n">e</span><span class="p">):</span>
<span class="n">R</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="k">return</span> <span class="n">R</span>
</div>
<div class="viewcode-block" id="compose"><a class="viewcode-back" href="../../../../reference/generated/networkx.algorithms.operators.binary.compose.html#networkx.algorithms.operators.binary.compose">[docs]</a><span class="k">def</span> <span class="nf">compose</span><span class="p">(</span><span class="n">G</span><span class="p">,</span> <span class="n">H</span><span class="p">,</span> <span class="n">name</span><span class="o">=</span><span class="bp">None</span><span class="p">):</span>
<span class="sd">"""Return a new graph of G composed with H.</span>
<span class="sd"> Composition is the simple union of the node sets and edge sets.</span>
<span class="sd"> The node sets of G and H need not be disjoint.</span>
<span class="sd"> Parameters</span>
<span class="sd"> ----------</span>
<span class="sd"> G,H : graph</span>
<span class="sd"> A NetworkX graph</span>
<span class="sd"> name : string</span>
<span class="sd"> Specify name for new graph</span>
<span class="sd"> Returns</span>
<span class="sd"> -------</span>
<span class="sd"> C: A new graph with the same type as G</span>
<span class="sd"> Notes</span>
<span class="sd"> -----</span>
<span class="sd"> It is recommended that G and H be either both directed or both undirected.</span>
<span class="sd"> Attributes from H take precedent over attributes from G.</span>
<span class="sd"> """</span>
<span class="k">if</span> <span class="n">name</span> <span class="ow">is</span> <span class="bp">None</span><span class="p">:</span>
<span class="n">name</span><span class="o">=</span><span class="s">"compose( </span><span class="si">%s</span><span class="s">, </span><span class="si">%s</span><span class="s"> )"</span><span class="o">%</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">name</span><span class="p">,</span><span class="n">H</span><span class="o">.</span><span class="n">name</span><span class="p">)</span>
<span class="n">R</span><span class="o">=</span><span class="n">G</span><span class="o">.</span><span class="n">__class__</span><span class="p">()</span>
<span class="n">R</span><span class="o">.</span><span class="n">name</span><span class="o">=</span><span class="n">name</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_nodes_from</span><span class="p">(</span><span class="n">H</span><span class="o">.</span><span class="n">nodes</span><span class="p">())</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_nodes_from</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">nodes</span><span class="p">())</span>
<span class="k">if</span> <span class="n">H</span><span class="o">.</span><span class="n">is_multigraph</span><span class="p">():</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_edges_from</span><span class="p">(</span><span class="n">H</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">keys</span><span class="o">=</span><span class="bp">True</span><span class="p">,</span><span class="n">data</span><span class="o">=</span><span class="bp">True</span><span class="p">))</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_edges_from</span><span class="p">(</span><span class="n">H</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">data</span><span class="o">=</span><span class="bp">True</span><span class="p">))</span>
<span class="k">if</span> <span class="n">G</span><span class="o">.</span><span class="n">is_multigraph</span><span class="p">():</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_edges_from</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">keys</span><span class="o">=</span><span class="bp">True</span><span class="p">,</span><span class="n">data</span><span class="o">=</span><span class="bp">True</span><span class="p">))</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">R</span><span class="o">.</span><span class="n">add_edges_from</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">edges_iter</span><span class="p">(</span><span class="n">data</span><span class="o">=</span><span class="bp">True</span><span class="p">))</span>
<span class="c"># add node attributes, H attributes take precedent over G attributes</span>
<span class="n">R</span><span class="o">.</span><span class="n">node</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">node</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">node</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">H</span><span class="o">.</span><span class="n">node</span><span class="p">)</span>
<span class="c"># add graph attributes, H attributes take precedent over G attributes</span>
<span class="n">R</span><span class="o">.</span><span class="n">graph</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">G</span><span class="o">.</span><span class="n">graph</span><span class="p">)</span>
<span class="n">R</span><span class="o">.</span><span class="n">graph</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">H</span><span class="o">.</span><span class="n">graph</span><span class="p">)</span>
<span class="k">return</span> <span class="n">R</span></div>
</pre></div>
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