Consistent return type in dictionary output of rescale_layout and rescale_layout_dict (#5091)

* changed tuple to np.array

* changed return to zip

* modified unittest to match rescale_layout_dict return type

* modified doctest rescale_layout_dict

* added import statement to doctest; test pass

* Add release note about change in return type.

Co-authored-by: Ross Barnowski <rossbar@berkeley.edu>

3 files changed, 26 insertions, 7 deletions

diff --git a/doc/release/release_dev.rst b/doc/release/release_dev.rst
index 0c4b8054..a779ab16 100644
--- a/doc/release/release_dev.rst
+++ b/doc/release/release_dev.rst
@@ -38,6 +38,10 @@ Improvements
 API Changes
 -----------
 
+- The values in the dictionary returned by
+  `~networkx.drawing.layout.rescale_layout_dict` are now `numpy.ndarray` objects
+  instead of tuples. This makes the return type of ``rescale_layout_dict``
+  consistent with that of all of the other layout functions.
 
 Deprecations
 ------------
diff --git a/networkx/drawing/layout.py b/networkx/drawing/layout.py
index 8a6e4ace..f0aa0b4b 100644
--- a/networkx/drawing/layout.py
+++ b/networkx/drawing/layout.py
@@ -1167,13 +1167,14 @@ def rescale_layout_dict(pos, scale=1):
 
     Examples
     --------
-    >>> pos = {0: (0, 0), 1: (1, 1), 2: (0.5, 0.5)}
+    >>> import numpy as np
+    >>> pos = {0: np.array((0, 0)), 1: np.array((1, 1)), 2: np.array((0.5, 0.5))}
     >>> nx.rescale_layout_dict(pos)
-    {0: (-1.0, -1.0), 1: (1.0, 1.0), 2: (0.0, 0.0)}
+    {0: array([-1., -1.]), 1: array([1., 1.]), 2: array([0., 0.])}
 
-    >>> pos = {0: (0, 0), 1: (-1, 1), 2: (-0.5, 0.5)}
+    >>> pos = {0: np.array((0, 0)), 1: np.array((-1, 1)), 2: np.array((-0.5, 0.5))}
     >>> nx.rescale_layout_dict(pos, scale=2)
-    {0: (2.0, -2.0), 1: (-2.0, 2.0), 2: (0.0, 0.0)}
+    {0: array([ 2., -2.]), 1: array([-2.,  2.]), 2: array([0., 0.])}
 
     See Also
     --------
@@ -1185,4 +1186,4 @@ def rescale_layout_dict(pos, scale=1):
         return {}
     pos_v = np.array(list(pos.values()))
     pos_v = rescale_layout(pos_v, scale=scale)
-    return {k: tuple(v) for k, v in zip(pos.keys(), pos_v)}
+    return dict(zip(pos, pos_v))
diff --git a/networkx/drawing/tests/test_layout.py b/networkx/drawing/tests/test_layout.py
index e878f5e7..183c9fbc 100644
--- a/networkx/drawing/tests/test_layout.py
+++ b/networkx/drawing/tests/test_layout.py
@@ -395,6 +395,20 @@ class TestLayout:
         G = nx.empty_graph(3)
         vpos = {0: (0, 0), 1: (1, 1), 2: (0.5, 0.5)}
         s_vpos = nx.rescale_layout_dict(vpos)
-        assert s_vpos == {0: (-1, -1), 1: (1, 1), 2: (0, 0)}
+
+        expectation = {
+            0: np.array((-1, -1)),
+            1: np.array((1, 1)),
+            2: np.array((0, 0)),
+        }
+        for k, v in expectation.items():
+            assert (s_vpos[k] == v).all()
         s_vpos = nx.rescale_layout_dict(vpos, scale=2)
-        assert s_vpos == {0: (-2, -2), 1: (2, 2), 2: (0, 0)}
+
+        expectation = {
+            0: np.array((-2, -2)),
+            1: np.array((2, 2)),
+            2: np.array((0, 0)),
+        }
+        for k, v in expectation.items():
+            assert (s_vpos[k] == v).all()