Update truncate() documentation and testcases

pandas/core/generic.py

@@ -4633,14 +4633,15 @@ def tshift(self, periods=1, freq=None, axis=0):
 
  def truncate(self, before=None, after=None, axis=None, copy=True):
  """Truncates a sorted NDFrame before and/or after some particular
- dates.
+ index value. If the axis contains only datetime values, before/after
+ parameters are converted to datetime values.
 
  Parameters
  ----------
  before : date
- Truncate before date
+ Truncate before index value
  after : date
- Truncate after date
+ Truncate after index value
  axis : the truncation axis, defaults to the stat axis
  copy : boolean, default is True,
  return a copy of the truncated section

pandas/tests/test_generic.py

@@ -809,6 +809,17 @@ def test_describe_none(self):
  expected = Series([0, 0], index=['count', 'unique'], name='None')
  assert_series_equal(noneSeries.describe(), expected)
 
+ def test_truncate_outofbounds(self):
+ # GH11382
+ small = pd.Series(data=range(int(2e3)), index=range(int(2e3)))
+ assert_series_equal(small.truncate(), small)
+ assert_series_equal(small.truncate(before=0, after=3e3), small)
+ assert_series_equal(small.truncate(before=-1, after=2e3), small)
+ big = pd.Series(data=range(int(2e6)), index=range(int(2e6)))
+ assert_series_equal(big.truncate(), big)
+ assert_series_equal(big.truncate(before=0, after=3e6), big)
+ assert_series_equal(big.truncate(before=-1, after=2e6), big)
+
  def test_to_xarray(self):
 
  tm._skip_if_no_xarray()