Use drawstyle instead of linestyle in plot.step.

doc/whats-new.rst

@@ -20,7 +20,12 @@ v0.16.0 (unreleased)
 
 Breaking changes
 ~~~~~~~~~~~~~~~~
-
+- Alternate draw styles for :py:meth:`plot.step` must be passed using the
+  ``drawstyle`` (or ``ds``) keyword argument, instead of the ``linestyle`` (or
+  ``ls``) keyword argument, in line with the `upstream change in Matplotlib
+  <https://matplotlib.org/api/prev_api_changes/api_changes_3.1.0.html#passing-a-line2d-s-drawstyle-together-with-the-linestyle-is-deprecated>`_.
+  (:pull:`3274`)
+  By `Elliott Sales de Andrade <https://github.com/QuLogic>`_
 
 New Features
 ~~~~~~~~~~~~

xarray/plot/plot.py

@@ -329,7 +329,7 @@ def line(
     return primitive
 
 
-def step(darray, *args, where="pre", linestyle=None, ls=None, **kwargs):
+def step(darray, *args, where="pre", drawstyle=None, ds=None, **kwargs):
     """
     Step plot of DataArray index against values
 
@@ -359,16 +359,16 @@ def step(darray, *args, where="pre", linestyle=None, ls=None, **kwargs):
     if where not in {"pre", "post", "mid"}:
         raise ValueError("'where' argument to step must be " "'pre', 'post' or 'mid'")
 
-    if ls is not None:
-        if linestyle is None:
-            linestyle = ls
+    if ds is not None:
+        if drawstyle is None:
+            drawstyle = ds
         else:
-            raise TypeError("ls and linestyle are mutually exclusive")
-    if linestyle is None:
-        linestyle = ""
-    linestyle = "steps-" + where + linestyle
+            raise TypeError("ds and drawstyle are mutually exclusive")
+    if drawstyle is None:
+        drawstyle = ""
+    drawstyle = "steps-" + where + drawstyle
 
-    return line(darray, *args, linestyle=linestyle, **kwargs)
+    return line(darray, *args, drawstyle=drawstyle, **kwargs)
 
 
 def hist(

xarray/plot/utils.py

@@ -465,7 +465,7 @@ def _resolve_intervals_1dplot(xval, yval, xlabel, ylabel, kwargs):
     """
 
     # Is it a step plot? (see matplotlib.Axes.step)
-    if kwargs.get("linestyle", "").startswith("steps-"):
+    if kwargs.get("drawstyle", "").startswith("steps-"):
 
         # Convert intervals to double points
         if _valid_other_type(np.array([xval, yval]), [pd.Interval]):
@@ -476,7 +476,7 @@ def _resolve_intervals_1dplot(xval, yval, xlabel, ylabel, kwargs):
             yval, xval = _interval_to_double_bound_points(yval, xval)
 
         # Remove steps-* to be sure that matplotlib is not confused
-        del kwargs["linestyle"]
+        del kwargs["drawstyle"]
 
     # Is it another kind of plot?
     else:

xarray/tests/test_plot.py

@@ -591,6 +591,10 @@ def setUp(self):
     def test_step(self):
         self.darray[0, 0].plot.step()
 
+    @pytest.mark.parametrize("ds", ["pre", "post", "mid"])
+    def test_step_with_drawstyle(self, ds):
+        self.darray[0, 0].plot.step(drawstyle=ds)
+
     def test_coord_with_interval_step(self):
         """Test step plot with intervals."""
         bins = [-1, 0, 1, 2]