ADD: Add add_field_like method to xradar (#1718)

pyart/xradar/accessor.py

@@ -494,6 +494,51 @@ def add_field(self, field_name, dic, replace_existing=False):
             self.xradar[f"sweep_{sweep}"].ds = sweep_ds
         return
 
+    def add_field_like(
+        self, existing_field_name, field_name, data, replace_existing=False
+    ):
+        """
+        Add a field to the object with metadata from a existing field.
+
+        Note that the data parameter is not copied by this method.
+        If data refers to a 'data' array from an existing field dictionary, a
+        copy should be made within or prior to using this method. If this is
+        not done the 'data' key in both field dictionaries will point to the
+        same NumPy array and modification of one will change the second. To
+        copy NumPy arrays use the copy() method. See the Examples section
+        for how to create a copy of the 'reflectivity' field as a field named
+        'reflectivity_copy'.
+
+        Parameters
+        ----------
+        existing_field_name : str
+            Name of an existing field to take metadata from when adding
+            the new field to the object.
+        field_name : str
+            Name of the field to add to the dictionary of fields.
+        data : array
+            Field data. A copy of this data is not made, see the note above.
+        replace_existing : bool, optional
+            True to replace the existing field with key field_name if it
+            exists, loosing any existing data. False will raise a ValueError
+            when the field already exists.
+
+        Examples
+        --------
+        >>> radar.add_field_like('reflectivity', 'reflectivity_copy',
+        ...                      radar.fields['reflectivity']['data'].copy())
+
+        """
+        if existing_field_name not in self.fields:
+            err = f"field {existing_field_name} does not exist in object"
+            raise ValueError(err)
+        dic = {}
+        for k, v in self.fields[existing_field_name].items():
+            if k != "data":
+                dic[k] = v
+        dic["data"] = data
+        return self.add_field(field_name, dic, replace_existing=replace_existing)
+
     def get_field(self, sweep, field_name, copy=False):
         """
         Return the field data for a given sweep.

tests/xradar/test_accessor.py

@@ -83,6 +83,11 @@ def test_add_field(filename=filename):
     radar.add_field("reflectivity", new_field)
     assert "reflectivity" in radar.fields
     assert radar["sweep_0"]["reflectivity"].shape == radar["sweep_0"]["DBZ"].shape
+    # Test add field like as well
+    radar.add_field_like("reflectivity", "test", new_field["data"])
+    assert "test" in radar.fields
+    assert "data" in radar.fields["test"]
+    assert radar.fields["test"]["units"] == "dBZ"
 
 
 def test_grid(filename=filename):