ndrolling repr fix

Author: fujiisoup

xarray/core/rolling.py

@@ -99,8 +99,8 @@ def __repr__(self):
         """provide a nice str repr of our rolling object"""
 
         attrs = [
-            "{k}->{v}".format(k=k, v=getattr(self, k))
-            for k in list(self.dim) + self.window + self.center + [self.min_periods]
+            "{k}->{v}{c}".format(k=k, v=w, c="(center)" if c else "")
+            for k, w, c in zip(self.dim, self.window, self.center)
         ]
         return "{klass} [{attrs}]".format(
             klass=self.__class__.__name__, attrs=",".join(attrs)

xarray/tests/test_dataarray.py

@@ -6178,6 +6178,8 @@ def test_rolling_iter(da):
                 actual.values[actual.values.nonzero()],
                 expected.values[expected.values.nonzero()],
             )
+    # no error
+    repr(rolling_obj)
 
 
 def test_rolling_doc(da):