Backport PR #18243: Fix reshape list of strings

QuLogic · QuLogic · commit bcbabb36b3ed · 2020-08-13T18:18:21.000-04:00
diff --git a/lib/matplotlib/cbook/__init__.py b/lib/matplotlib/cbook/__init__.py
@@ -1367,7 +1367,10 @@ def _reshape_2D(X, name):
     result = []
     is_1d = True
     for xi in X:
-        if isinstance(xi, collections.abc.Iterable):
+        # check if this is iterable, except for strings which we
+        # treat as singletons.
+        if (isinstance(xi, collections.abc.Iterable) and
+                not isinstance(xi, str)):
             is_1d = False
         xi = np.asanyarray(xi)
         nd = np.ndim(xi)
diff --git a/lib/matplotlib/tests/test_category.py b/lib/matplotlib/tests/test_category.py
@@ -269,3 +269,10 @@ def test_mixed_type_update_exception(self, ax, plotter, xdata):
         with pytest.raises(TypeError):
             plotter(ax, [0, 3], [1, 3])
             plotter(ax, xdata, [1, 2])
+
+
+def test_hist():
+    fig, ax = plt.subplots()
+    n, bins, patches = ax.hist(['a', 'b', 'a', 'c', 'ff'])
+    assert n.shape == (10,)
+    np.testing.assert_allclose(n, [2., 0., 0., 1., 0., 0., 1., 0., 0., 1.])
diff --git a/lib/matplotlib/tests/test_cbook.py b/lib/matplotlib/tests/test_cbook.py
@@ -545,6 +545,12 @@ def __getitem__(self, item):
     assert len(xnew) == 1
     assert isinstance(xnew[0], ArraySubclass)
 
+    # check list of strings:
+    x = ['a', 'b', 'c', 'c', 'dd', 'e', 'f', 'ff', 'f']
+    xnew = cbook._reshape_2D(x, 'x')
+    assert len(xnew[0]) == len(x)
+    assert isinstance(xnew[0], np.ndarray)
+
 
 def test_contiguous_regions():
     a, b, c = 3, 4, 5
