Support drop* and *_coords methods (#145)

* implement names and labels

* no need of _get_with_key

* add tests

* fix tests

* add what's new

.github/workflows/ci.yaml

@@ -2,7 +2,7 @@ name: CI
 on:
   push:
     branches:
-      - "*"
+      - "main"
   pull_request:
     branches:
       - "*"

.github/workflows/pre-commit.yaml

@@ -2,7 +2,7 @@ name: pre-commit
 
 on:
   push:
-    branches: "*"
+    branches: "main"
   pull_request:
     branches:
       - "*"

cf_xarray/accessor.py

@@ -376,7 +376,12 @@ def _get_with_standard_name(
     "dims_dict": (_get_axis_coord,),  # swap_dims, rename_dims
     "shifts": (_get_axis_coord,),  # shift, roll
     "pad_width": (_get_axis_coord,),  # shift, roll
-    # "names": something_with_all_valid_keys? # set_coords, reset_coords
+    "names": (
+        _get_axis_coord,
+        _get_measure,
+        _get_with_standard_name,
+    ),  # set_coords, reset_coords, drop_vars
+    "labels": (_get_axis_coord, _get_measure, _get_with_standard_name),  # drop
     "coords": (_get_axis_coord,),  # interp
     "indexers": (_get_axis_coord,),  # sel, isel, reindex
     # "indexes": (_get_axis_coord,),  # set_index

cf_xarray/tests/test_accessor.py

@@ -4,6 +4,7 @@
 import pytest
 import xarray as xr
 from matplotlib import pyplot as plt
+from xarray import Dataset
 from xarray.testing import assert_allclose, assert_identical
 
 import cf_xarray  # noqa
@@ -665,3 +666,45 @@ def test_standard_name_mapper():
     actual = da.cf.sortby("standard_label")
     expected = da.sortby("label")
     assert_identical(actual, expected)
+
+
+@pytest.mark.parametrize("obj", objects)
+@pytest.mark.parametrize("attr", ["drop", "drop_vars", "set_coords"])
+@pytest.mark.filterwarnings("ignore:dropping .* using `drop` .* deprecated")
+def test_drop_vars_and_set_coords(obj, attr):
+
+    # DataArray object has no attribute set_coords
+    if not isinstance(obj, Dataset) and attr == "set_coords":
+        return
+
+    # Get attribute
+    expected = getattr(obj, attr)
+    actual = getattr(obj.cf, attr)
+
+    # Axis
+    assert_identical(expected("lon"), actual("X"))
+    # Coordinate
+    assert_identical(expected("lon"), actual("longitude"))
+    # Cell measure
+    assert_identical(expected("cell_area"), actual("area"))
+    # Variables
+    if isinstance(obj, Dataset):
+        assert_identical(expected("air"), actual("air_temperature"))
+        assert_identical(expected(obj.variables), actual(obj.cf.keys()))
+
+
+@pytest.mark.parametrize("obj", objects)
+def test_drop_sel_and_reset_coords(obj):
+
+    # Axis
+    assert_identical(obj.drop_sel(lat=75), obj.cf.drop_sel(Y=75))
+    # Coordinate
+    assert_identical(obj.drop_sel(lat=75), obj.cf.drop_sel(latitude=75))
+
+    # Cell measure
+    assert_identical(obj.reset_coords("cell_area"), obj.cf.reset_coords("area"))
+    # Variable
+    if isinstance(obj, Dataset):
+        assert_identical(
+            obj.reset_coords("air"), obj.cf.reset_coords("air_temperature")
+        )

doc/whats-new.rst

@@ -6,6 +6,7 @@ What's New
 v0.4.1 (unreleased)
 ===================
 
+- Support for ``.drop()``, ``.drop_vars()``, ``.drop_sel()``, ``.set_coords()``, ``.reset_coords()``. By `Mattia Almansi`_.
 - Support for using ``standard_name`` in more functions. (:pr:`128`) By `Deepak Cherian`_
 - Allow ``DataArray.cf[]`` with standard names. By `Deepak Cherian`_
 - Rewrite the ``values`` of ``.cf.coords`` and ``.cf.data_vars`` with objects returned