repr string for pd.Grouper

pandas/core/groupby.py

@@ -9,7 +9,7 @@
 
 from pandas.compat import (
     zip, range, lzip,
-    callable, map
+    callable, map, signature
 )
 
 from pandas import compat
@@ -234,6 +234,8 @@ class Grouper(object):
     >>> df.groupby(Grouper(level='date', freq='60s', axis=1))
     """
 
+    _attributes = ['key', 'level', 'freq', 'axis', 'sort']
+
     def __new__(cls, *args, **kwargs):
         if kwargs.get('freq') is not None:
             from pandas.core.resample import TimeGrouper
@@ -333,6 +335,17 @@ def _set_grouper(self, obj, sort=False):
     def groups(self):
         return self.grouper.groups
 
+    def __repr__(self):
+        grouper_defaults = compat.signature(self.__init__).defaults
+        sd = self.__dict__
+        attrs = collections.OrderedDict()
+        for k, v in zip(self._attributes, grouper_defaults):
+            if k in sd and sd[k] != v:
+                attrs[k] = sd[k]
+        attrs = ", ".join("{}={!r}".format(k, v) for k, v in attrs.items())
+        cls_name = self.__class__.__name__
+        return "{}({})".format(cls_name, attrs)
+
 
 class GroupByPlot(PandasObject):
     """

pandas/core/resample.py

@@ -1,4 +1,5 @@
 from datetime import timedelta
+import collections
 import numpy as np
 import warnings
 import copy
@@ -1026,13 +1027,18 @@ class TimeGrouper(Grouper):
     directly from the associated object
     """
 
+    _attributes = ['key', 'level', 'freq', 'axis', 'sort', 'closed', 'label',
+                   'how', 'nperiods', 'fill_method', 'limit',
+                   'loffset', 'kind', 'convention', 'base']
+    _end_types = {'M', 'A', 'Q', 'BM', 'BA', 'BQ', 'W'}
+
     def __init__(self, freq='Min', closed=None, label=None, how='mean',
                  nperiods=None, axis=0,
                  fill_method=None, limit=None, loffset=None, kind=None,
                  convention=None, base=0, **kwargs):
         freq = to_offset(freq)
 
-        end_types = set(['M', 'A', 'Q', 'BM', 'BA', 'BQ', 'W'])
+        end_types = self._end_types
         rule = freq.rule_code
         if (rule in end_types or
                 ('-' in rule and rule[:rule.find('-')] in end_types)):
@@ -1047,6 +1053,7 @@ def __init__(self, freq='Min', closed=None, label=None, how='mean',
                 label = 'left'
 
         self.closed = closed
+        self.freq = freq
         self.label = label
         self.nperiods = nperiods
         self.kind = kind

pandas/tests/test_resample.py

@@ -3177,6 +3177,14 @@ def setup_method(self, method):
         self.ts = Series(np.random.randn(1000),
                          index=date_range('1/1/2000', periods=1000))
 
+    def test_timegrouper_repr(self):
+        # Added in GH17727
+        result = repr(TimeGrouper(key='key', freq='50Min', label='right'))
+        expected = ("TimeGrouper(key='key', freq=<50 * Minutes>, axis=0,"
+                    " sort=True, closed='left', label='right', how='mean', "
+                    "loffset=None)")
+        assert result == expected
+
     def test_apply(self):
         with tm.assert_produces_warning(FutureWarning,
                                         check_stacklevel=False):