matplotlib
diff --git a/‎lib/matplotlib/contour.py
Copy file name to clipboardExpand all lines: lib/matplotlib/contour.py
+18-3Lines changed: 18 additions & 3 deletions b/‎lib/matplotlib/contour.py
Copy file name to clipboardExpand all lines: lib/matplotlib/contour.py
+18-3Lines changed: 18 additions & 3 deletions
diff --git a/‎lib/matplotlib/tests/test_contour.py
Copy file name to clipboardExpand all lines: lib/matplotlib/tests/test_contour.py
+22Lines changed: 22 additions & 0 deletions b/‎lib/matplotlib/tests/test_contour.py
Copy file name to clipboardExpand all lines: lib/matplotlib/tests/test_contour.py
+22Lines changed: 22 additions & 0 deletions
@@ -1386,7 +1386,7 @@ def _process_args(self, *args, corner_mask=None, algorithm=None, **kwargs):
         """
         Process args and kwargs.
         """
-        if isinstance(args[0], QuadContourSet):
+        if args and isinstance(args[0], QuadContourSet):
             if self.levels is None:
                 self.levels = args[0].levels
             self.zmin = args[0].zmin
@@ -1446,11 +1446,26 @@ def _contour_args(self, args, kwargs):
         else:
             fn = 'contour'
         nargs = len(args)
-        if nargs <= 2:
+        if "X" in kwargs and "Y" in kwargs and "Z" in kwargs:
+            x, y, z = self._check_xyz(
+                [
+                    kwargs.pop("X"),
+                    kwargs.pop("Y"),
+                    kwargs.pop("Z")
+                ],
+                kwargs
+            )
+        elif (("X" in kwargs) ^ ("Y" in kwargs)) and "Z" in kwargs:
+            raise KeyError("Both 'X' and 'Y' must be passed as kwargs. "
+                           "Passing only one of the two is not allowed.")
+        elif "Z" in kwargs:
+            z = ma.asarray(kwargs.pop("Z"), dtype=np.float64)
+            x, y = self._initialize_x_y(z)
+        elif 0 < nargs <= 2:
             z = ma.asarray(args[0], dtype=np.float64)
             x, y = self._initialize_x_y(z)
             args = args[1:]
-        elif nargs <= 4:
+        elif 2 < nargs <= 4:
             x, y, z = self._check_xyz(args[:3], kwargs)
             args = args[3:]
         else:
 
@@ -693,3 +693,25 @@ def test_contour_remove():
     assert ax.get_children() != orig_children
     cs.remove()
     assert ax.get_children() == orig_children
+
+
+def test_contour_z_kwargonly():
+    # Smoke test for GH#24743
+    # Passing only kwargs
+    plt.contour(Z=np.random.rand(30, 30))
+
+
+def test_contour_xyz_kwargsonly():
+    plt.contour(
+        X=np.random.rand(30, 30),
+        Y=np.random.rand(30, 30),
+        Z=np.random.rand(30, 30)
+    )
+
+
+def test_contour_either_xy():
+    with pytest.raises(KeyError):
+        plt.contour(
+            X=np.random.rand(30, 30),
+            Z=np.random.rand(30, 30)
+        )