[docs] amend Dataset.assign_coords example (pydata#6336)

* remove np.random uses

* fix one copy-paste artifact 'description:  Temperature data'

xarray/core/common.py

@@ -494,46 +494,47 @@ def assign_coords(self, coords=None, **coords_kwargs):
 
         Convert `Dataset` longitude coordinates from 0-359 to -180-179:
 
-        >>> np.random.seed(0)
+        >>> temperature = np.linspace(20, 32, num=16).reshape(2, 2, 4)
+        >>> precipitation = 2 * np.identity(4).reshape(2, 2, 4)
         >>> ds = xr.Dataset(
         ...     data_vars=dict(
-        ...         temperature=(["x", "y", "time"], 15 + 8 * np.random.randn(2, 2, 3)),
-        ...         precipitation=(["x", "y", "time"], 10 * np.random.rand(2, 2, 3)),
+        ...         temperature=(["x", "y", "time"], temperature),
+        ...         precipitation=(["x", "y", "time"], precipitation),
         ...     ),
         ...     coords=dict(
         ...         lon=(["x", "y"], [[260.17, 260.68], [260.21, 260.77]]),
         ...         lat=(["x", "y"], [[42.25, 42.21], [42.63, 42.59]]),
-        ...         time=pd.date_range("2014-09-06", periods=3),
-        ...         reference_time=pd.Timestamp("2014-09-05")
+        ...         time = pd.date_range("2014-09-06", periods=4),
+        ...         reference_time = pd.Timestamp("2014-09-05")
         ...     ),
         ...     attrs=dict(description="Weather-related data"),
         ... )
         >>> ds
         <xarray.Dataset>
-        Dimensions:         (x: 2, y: 2, time: 3)
+        Dimensions:         (x: 2, y: 2, time: 4)
         Coordinates:
             lon             (x, y) float64 260.2 260.7 260.2 260.8
             lat             (x, y) float64 42.25 42.21 42.63 42.59
-          * time            (time) datetime64[ns] 2014-09-06 2014-09-07 2014-09-08
+          * time            (time) datetime64[ns] 2014-09-06 2014-09-07 ... 2014-09-09
             reference_time  datetime64[ns] 2014-09-05
         Dimensions without coordinates: x, y
         Data variables:
-            temperature     (x, y, time) float64 29.11 18.2 22.83 ... 18.28 16.15 26.63
-            precipitation   (x, y, time) float64 5.68 9.256 0.7104 ... 7.992 4.615 7.805
+            temperature     (x, y, time) float64 20.0 20.8 21.6 22.4 ... 30.4 31.2 32.0
+            precipitation   (x, y, time) float64 2.0 0.0 0.0 0.0 0.0 ... 0.0 0.0 0.0 2.0
         Attributes:
-            description:  Temperature data
+            description:  Weather-related data
         >>> ds.assign_coords(lon=(((ds.lon + 180) % 360) - 180))
         <xarray.Dataset>
-        Dimensions:         (x: 2, y: 2, time: 3)
+        Dimensions:         (x: 2, y: 2, time: 4)
         Coordinates:
             lon             (x, y) float64 -99.83 -99.32 -99.79 -99.23
             lat             (x, y) float64 42.25 42.21 42.63 42.59
-          * time            (time) datetime64[ns] 2014-09-06 2014-09-07 2014-09-08
+          * time            (time) datetime64[ns] 2014-09-06 2014-09-07 ... 2014-09-09
             reference_time  datetime64[ns] 2014-09-05
         Dimensions without coordinates: x, y
         Data variables:
-            temperature     (x, y, time) float64 29.11 18.2 22.83 ... 18.28 16.15 26.63
-            precipitation   (x, y, time) float64 5.68 9.256 0.7104 ... 7.992 4.615 7.805
+            temperature     (x, y, time) float64 20.0 20.8 21.6 22.4 ... 30.4 31.2 32.0
+            precipitation   (x, y, time) float64 2.0 0.0 0.0 0.0 0.0 ... 0.0 0.0 0.0 2.0
         Attributes:
             description:  Weather-related data