Group supports item deletion; resolves #65

Author: alimanfoo

docs/release.rst

@@ -1,6 +1,9 @@
 Release notes
 =============
 
+* Group objects now support member deletion via ``del`` statement
+  ('#65 <https://github.com/alimanfoo/zarr/issues/65>'_)
+
 .. _release_2.0.1:
 
 2.0.1

zarr/hierarchy.py

@@ -9,7 +9,7 @@
 from zarr.attrs import Attributes
 from zarr.core import Array
 from zarr.storage import contains_array, contains_group, init_group, \
-    DictStore, DirectoryStore, group_meta_key, attrs_key, listdir
+    DictStore, DirectoryStore, group_meta_key, attrs_key, listdir, rmdir
 from zarr.creation import array, create, empty, zeros, ones, full, \
     empty_like, zeros_like, ones_like, full_like
 from zarr.util import normalize_storage_path, normalize_shape
@@ -302,6 +302,17 @@ def __getitem__(self, item):
         else:
             raise KeyError(item)
 
+    def __setitem__(self, item, value):
+        raise TypeError('item assignment not supported')
+
+    def __delitem__(self, item):
+        path = self._item_path(item)
+        if contains_array(self._store, path) or \
+                contains_group(self._store, path):
+            rmdir(self._store, path)
+        else:
+            raise KeyError(item)
+
     def group_keys(self):
         """Return an iterator over member names for groups only.
 

zarr/tests/test_hierarchy.py

@@ -485,6 +485,24 @@ def test_setitem(self):
         with assert_raises(TypeError):
             g['foo'] = 'bar'
 
+    def test_delitem(self):
+        g = self.create_group()
+        g.create_group('foo')
+        g.create_dataset('bar/baz', shape=100, chunks=10)
+        assert 'foo' in g
+        assert 'bar' in g
+        assert 'bar/baz' in g
+        try:
+            del g['bar']
+            with assert_raises(KeyError):
+                del g['xxx']
+        except NotImplementedError:
+            pass
+        else:
+            assert 'foo' in g
+            assert 'bar' not in g
+            assert 'bar/baz' not in g
+
     def test_array_creation(self):
         grp = self.create_group()