matplotlib
diff --git a/‎lib/matplotlib/colors.py
Copy file name to clipboardExpand all lines: lib/matplotlib/colors.py
+7-5Lines changed: 7 additions & 5 deletions b/‎lib/matplotlib/colors.py
Copy file name to clipboardExpand all lines: lib/matplotlib/colors.py
+7-5Lines changed: 7 additions & 5 deletions
diff --git a/‎lib/matplotlib/tests/test_colors.py
Copy file name to clipboardExpand all lines: lib/matplotlib/tests/test_colors.py
+4Lines changed: 4 additions & 0 deletions b/‎lib/matplotlib/tests/test_colors.py
Copy file name to clipboardExpand all lines: lib/matplotlib/tests/test_colors.py
+4Lines changed: 4 additions & 0 deletions
@@ -186,12 +186,14 @@ def _to_rgba_no_colorcycle(c, alpha=None):
             pass
         raise ValueError("Invalid RGBA argument: {!r}".format(orig_c))
     # tuple color.
-    # Python 2.7 / numpy 1.6 apparently require this to return builtin floats,
-    # not numpy floats.
-    try:
-        c = tuple(map(float, c))
-    except TypeError:
+    c = np.array(c)
+    if not np.can_cast(c.dtype, float) or c.ndim != 1:
+        # Test the dtype explicitly as `map(float, ...)`, `np.array(...,
+        # float)` and `np.array(...).astype(float)` all convert "0.5" to 0.5.
+        # Test dimensionality to reject single floats.
         raise ValueError("Invalid RGBA argument: {!r}".format(orig_c))
+    # Return a tuple to prevent the cached value from being modified.
+    c = tuple(c.astype(float))
     if len(c) not in [3, 4]:
         raise ValueError("RGBA sequence should have length 3 or 4")
     if len(c) == 3 and alpha is None:
 
@@ -645,6 +645,10 @@ def test_cn():
 def test_conversions():
     # to_rgba_array("none") returns a (0, 4) array.
     assert_array_equal(mcolors.to_rgba_array("none"), np.zeros((0, 4)))
+    # a list of grayscale levels, not a single color.
+    assert_array_equal(
+        mcolors.to_rgba_array([".2", ".5", ".8"]),
+        np.vstack([mcolors.to_rgba(c) for c in [".2", ".5", ".8"]]))
     # alpha is properly set.
     assert_equal(mcolors.to_rgba((1, 1, 1), .5), (1, 1, 1, .5))
     assert_equal(mcolors.to_rgba(".1", .5), (.1, .1, .1, .5))