Merge pull request #5459 from dwiel/groupby_comments

DOC: add basic documentation to some of the GroupBy properties and methods

Author: jreback

doc/source/api.rst

@@ -1112,6 +1112,42 @@ Conversion
    DatetimeIndex.to_pydatetime
 
 
+GroupBy
+-------
+.. currentmodule:: pandas.core.groupby
+
+GroupBy objects are returned by groupby calls: :func:`pandas.DataFrame.groupby`, :func:`pandas.Series.groupby`, etc.
+
+Indexing, iteration
+~~~~~~~~~~~~~~~~~~~
+.. autosummary::
+   :toctree: generated/
+   
+   GroupBy.__iter__
+   GroupBy.groups
+   GroupBy.indices
+   GroupBy.get_group
+
+Function application
+~~~~~~~~~~~~~~~~~~~~
+.. autosummary::
+   :toctree: generated/
+
+   GroupBy.apply
+   GroupBy.aggregate
+   GroupBy.transform
+
+Computations / Descriptive Stats
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.. autosummary::
+   :toctree: generated/
+   
+   GroupBy.mean
+   GroupBy.median
+   GroupBy.std
+   GroupBy.var
+   GroupBy.ohlc
+
 ..
     HACK - see github issue #4539. To ensure old links remain valid, include
     here the autosummaries with previous currentmodules as a comment and add

pandas/core/groupby.py

@@ -226,6 +226,7 @@ def __unicode__(self):
 
     @property
     def groups(self):
+        """ dict {group name -> group labels} """
         return self.grouper.groups
 
     @property
@@ -234,6 +235,7 @@ def ngroups(self):
 
     @property
     def indices(self):
+        """ dict {group name -> group indices} """
         return self.grouper.indices
 
     @property
@@ -310,6 +312,22 @@ def curried(x):
         return wrapper
 
     def get_group(self, name, obj=None):
+        """
+        Constructs NDFrame from group with provided name
+
+        Parameters
+        ----------
+        name : object
+            the name of the group to get as a DataFrame
+        obj : NDFrame, default None
+            the NDFrame to take the DataFrame out of.  If
+            it is None, the object groupby was called on will
+            be used
+
+        Returns
+        -------
+        group : type of obj
+        """
         if obj is None:
             obj = self.obj
 
@@ -838,6 +856,7 @@ def apply(self, f, data, axis=0):
 
     @cache_readonly
     def indices(self):
+        """ dict {group name -> group indices} """
         if len(self.groupings) == 1:
             return self.groupings[0].indices
         else:
@@ -884,6 +903,7 @@ def _max_groupsize(self):
 
     @cache_readonly
     def groups(self):
+        """ dict {group name -> group labels} """
         if len(self.groupings) == 1:
             return self.groupings[0].groups
         else: