DOC: add query examples (#5249)

* DOC: add query examples

* rm whitespace

Co-authored-by: Ray Bell <ray.bell@dtn.com>

Author: raybellwaves

xarray/core/dataarray.py

@@ -4452,6 +4452,17 @@ def query(
         Dataset.query
         pandas.eval
 
+        Examples
+        --------
+        >>> da = xr.DataArray(np.arange(0, 5, 1), dims="x", name="a")
+        >>> da
+        <xarray.DataArray 'a' (x: 5)>
+        array([0, 1, 2, 3, 4])
+        Dimensions without coordinates: x
+        >>> da.query(x="a > 2")
+        <xarray.DataArray 'a' (x: 2)>
+        array([3, 4])
+        Dimensions without coordinates: x
         """
 
         ds = self._to_dataset_whole(shallow_copy=True)

xarray/core/dataset.py

@@ -7235,6 +7235,25 @@ def query(
         Dataset.isel
         pandas.eval
 
+        Examples
+        --------
+        >>> a = np.arange(0, 5, 1)
+        >>> b = np.linspace(0, 1, 5)
+        >>> ds = xr.Dataset({"a": ("x", a), "b": ("x", b)})
+        >>> ds
+        <xarray.Dataset>
+        Dimensions:  (x: 5)
+        Dimensions without coordinates: x
+        Data variables:
+            a        (x) int64 0 1 2 3 4
+            b        (x) float64 0.0 0.25 0.5 0.75 1.0
+        >>> ds.query(x="a > 2")
+        <xarray.Dataset>
+        Dimensions:  (x: 2)
+        Dimensions without coordinates: x
+        Data variables:
+            a        (x) int64 3 4
+            b        (x) float64 0.75 1.0
         """
 
         # allow queries to be given either as a dict or as kwargs