Documentation and whats-new.

Including small fix to remove redundant '/' from group names.

Author: Stephen Pascoe

doc/source/io.rst

@@ -2677,6 +2677,19 @@ everything in the sub-store and BELOW, so be *careful*.
    store.remove('food')
    store
 
+You can walk through the group hierarchy using the ``walk`` method which
+will yield a tuple for each group key along with the relative keys of its contents.
+
+.. ipython:: python
+
+   for (path, subgroups, subkeys) in store.walk():
+       for subgroup in subgroups:
+           print('GROUP: {}/{}'.format(path, subgroup))
+       for subkey in subkeys:
+           key = '/'.join([path, subkey])
+           print('KEY: {}'.format(key))
+           print(store.get(key))
+
 .. _io.hdf5-types:
 
 Storing Mixed Types in a Table

doc/source/whatsnew/v0.17.0.txt

@@ -255,6 +255,8 @@ Other enhancements
 
     pd.concat([foo, bar, baz], 1)
 
+- New method ``HDFStore.walk`` will recursively walk the group hierarchy of a HDF5 file (:issue:`10932`)
+
 .. _whatsnew_0170.api:
 
 .. _whatsnew_0170.api_breaking:

pandas/io/pytables.py

@@ -1044,7 +1044,7 @@ def walk(self):
 
         Returns
         -------
-        A generator yielding tuples (`path`, `groups`, `frames`) where:
+        A generator yielding tuples (`path`, `groups`, `leaves`) where:
 
         - `path` is the full path to a group,
         - `groups` is a list of group names contained in `path`
@@ -1066,7 +1066,8 @@ def walk(self):
                         groups.append(child._v_name)
                 else:
                     leaves.append(child._v_name)
-            yield (g._v_pathname, groups, leaves)
+
+            yield (g._v_pathname.rstrip('/'), groups, leaves)
 
 
     def get_node(self, key):

pandas/io/tests/test_pytables.py

@@ -4825,9 +4825,7 @@ def test_walk(self):
             'a1': np.array([[1,2,3], [4,5,6]])
             }
 
-        with tm.ensure_clean('walk_groups.hdf') as filename:
-            store = HDFStore(filename, 'w')
-
+        with ensure_clean_store('walk_groups.hdf', mode='w') as store:
             store.put('/first_group/df1', objs['df1'])
             store.put('/first_group/df2', objs['df2'])
             store.put('/second_group/df3', objs['df3'])
@@ -4837,7 +4835,7 @@ def test_walk(self):
             store._handle.create_array(g1, 'a1', objs['a1'])
 
             expect = {
-                '/': (set(['first_group', 'second_group']), set()),
+                '': (set(['first_group', 'second_group']), set()),
                 '/first_group': (set(), set(['df1', 'df2'])),
                 '/second_group': (set(['third_group']), set(['df3', 's1'])),
                 '/second_group/third_group': (set(), set(['df4'])),