bug#10442 : fix, adding note and test

BUG #10442(test) : Convert datetimelike index to strings with astype(str) BUG#10422: note added bug#10442 : tests added bug#10442 : note udated BUG #10442(test) : Convert datetimelike index to strings with astype(str) bug#10442: fix, adding note and test bug#10442: fix, adding note and test

Author: Hamed Saljooghinejad

doc/source/whatsnew/v0.17.1.txt

@@ -17,6 +17,7 @@ Highlights include:
 
 Enhancements
 ~~~~~~~~~~~~
+- ``DatetimeIndex`` now supports conversion to strings with astype(str)(:issue:`10442`)
 
 - Support for ``compression`` (gzip/bz2) in :method:`DataFrame.to_csv` (:issue:`7615`)
 

pandas/tseries/index.py

@@ -756,6 +756,8 @@ def astype(self, dtype):
  return self.asi8.copy()
  elif dtype == _NS_DTYPE and self.tz is not None:
  return self.tz_convert('UTC').tz_localize(None)
+ elif dtype == str:
+ return self._shallow_copy(values=self.format(), infer=True)
  else: # pragma: no cover
  raise ValueError('Cannot cast DatetimeIndex to dtype %s' % dtype)
 

pandas/tseries/tests/test_base.py

@@ -45,6 +45,32 @@ def test_ops_properties_basic(self):
  self.assertEqual(s.day,10)
  self.assertRaises(AttributeError, lambda : s.weekday)
 
+ def test_astype_str(self):
+ # test astype string - #10442
+ result = date_range('2012-01-01', periods=4, name='test_name').astype(str)
+ expected = Index(['2012-01-01', '2012-01-02', '2012-01-03','2012-01-04'],
+ name='test_name', dtype=object)
+ tm.assert_index_equal(result, expected)
+
+ # test astype string with tz and name
+ result = date_range('2012-01-01', periods=3, name='test_name', tz='US/Eastern').astype(str)
+ expected = Index(['2012-01-01 00:00:00-05:00', '2012-01-02 00:00:00-05:00',
+ '2012-01-03 00:00:00-05:00'], name='test_name', dtype=object)
+ tm.assert_index_equal(result, expected)
+
+ # test astype string with freqH and name
+ result = date_range('1/1/2011', periods=3, freq='H', name='test_name').astype(str)
+ expected = Index(['2011-01-01 00:00:00', '2011-01-01 01:00:00', '2011-01-01 02:00:00'],
+ name='test_name', dtype=object)
+ tm.assert_index_equal(result, expected)
+
+ # test astype string with freqH and timezone
+ result = date_range('3/6/2012 00:00', periods=2, freq='H',
+ tz='Europe/London', name='test_name').astype(str)
+ expected = Index(['2012-03-06 00:00:00+00:00', '2012-03-06 01:00:00+00:00'],
+ dtype=object, name='test_name')
+ tm.assert_index_equal(result, expected)
+
  def test_asobject_tolist(self):
  idx = pd.date_range(start='2013-01-01', periods=4, freq='M', name='idx')
  expected_list = [pd.Timestamp('2013-01-31'), pd.Timestamp('2013-02-28'),
@@ -503,7 +529,6 @@ def test_infer_freq(self):
  tm.assert_index_equal(idx, result)
  self.assertEqual(result.freq, freq)
 
-
 class TestTimedeltaIndexOps(Ops):
 
  def setUp(self):

pandas/tseries/tests/test_timeseries.py

@@ -2223,6 +2223,7 @@ def test_append_join_nondatetimeindex(self):
  # it works
  rng.join(idx, how='outer')
 
+
  def test_astype(self):
  rng = date_range('1/1/2000', periods=10)
 
@@ -2235,6 +2236,17 @@ def test_astype(self):
  expected = date_range('1/1/2000', periods=10, tz='US/Eastern').tz_convert('UTC').tz_localize(None)
  tm.assert_index_equal(result, expected)
 
+ # BUG#10442 : testing astype(str) is correct for Series/DatetimeIndex
+ result = pd.Series(pd.date_range('2012-01-01', periods=3)).astype(str)
+ expected = pd.Series(['2012-01-01', '2012-01-02', '2012-01-03'], dtype=object)
+ tm.assert_series_equal(result, expected)
+
+ result = Series(pd.date_range('2012-01-01', periods=3, tz='US/Eastern')).astype(str)
+ expected = Series(['2012-01-01 00:00:00-05:00', '2012-01-02 00:00:00-05:00', '2012-01-03 00:00:00-05:00'],
+ dtype=object)
+ tm.assert_series_equal(result, expected)
+
+
  def test_to_period_nofreq(self):
  idx = DatetimeIndex(['2000-01-01', '2000-01-02', '2000-01-04'])
  self.assertRaises(ValueError, idx.to_period)