Fix pydot colon check node-to-str conversion (#5809)

2 files changed, 16 insertions, 3 deletions

diff --git a/networkx/drawing/nx_pydot.py b/networkx/drawing/nx_pydot.py
index 2b01f59f..2055eb32 100644
--- a/networkx/drawing/nx_pydot.py
+++ b/networkx/drawing/nx_pydot.py
@@ -432,15 +432,15 @@ def pydot_layout(G, prog="neato", root=None):
 
     node_pos = {}
     for n in G.nodes():
-        n = str(n)
+        str_n = str(n)
         # Explicitly catch nodes with ":" in node names or nodedata.
-        if _check_colon_quotes(n):
+        if _check_colon_quotes(str_n):
             raise ValueError(
                 f'Node names and node attributes should not contain ":" unless they are quoted with "".\
                 For example the string \'attribute:data1\' should be written as \'"attribute:data1"\'.\
                 Please refer https://github.com/pydot/pydot/issues/258'
             )
-        pydot_node = pydot.Node(n).get_name()
+        pydot_node = pydot.Node(str_n).get_name()
         node = Q.get_node(pydot_node)
 
         if isinstance(node, list):
diff --git a/networkx/drawing/tests/test_pydot.py b/networkx/drawing/tests/test_pydot.py
index 2e5e3ec6..90d025e2 100644
--- a/networkx/drawing/tests/test_pydot.py
+++ b/networkx/drawing/tests/test_pydot.py
@@ -175,3 +175,16 @@ def test_hashable_pydot(graph_type):
     assert {str(i) for i in G.nodes()} == set(
         nx.nx_pydot.from_pydot(nx.nx_pydot.to_pydot(G)).nodes
     )
+
+
+def test_pydot_numrical_name():
+    G = nx.Graph()
+    G.add_edges_from([("A", "B"), (0, 1)])
+    graph_layout = nx.nx_pydot.pydot_layout(G, prog="dot")
+    assert isinstance(graph_layout, dict)
+    assert "0" not in graph_layout
+    assert 0 in graph_layout
+    assert "1" not in graph_layout
+    assert 1 in graph_layout
+    assert "A" in graph_layout
+    assert "B" in graph_layout