ERR: raise on missing values in pd.pivot_table #14938 (#14965)

doc/source/whatsnew/v0.20.0.txt

@@ -301,3 +301,4 @@ Bug Fixes
 - Bug in ``pd.unique()`` in which unsigned 64-bit integers were causing overflow (:issue:`14915`)
 - Require at least 0.23 version of cython to avoid problems with character encodings (:issue:`14699`)
 - Bug in converting object elements of array-like objects to unsigned 64-bit integers (:issue:`4471`)
+- Bug in ``pd.pivot_table()`` where no error was raised when values argument was not in the columns (:issue:`14938`)

pandas/tests/groupby/test_groupby.py

@@ -5746,6 +5746,20 @@ def test_group_shift_with_null_key(self):
 
  assert_frame_equal(result, expected)
 
+ def test_pivot_table_values_key_error(self):
+ # This test is designed to replicate the error in issue #14938
+ df = pd.DataFrame({'eventDate':
+ pd.date_range(pd.datetime.today(),
+ periods=20, freq='M').tolist(),
+ 'thename': range(0, 20)})
+
+ df['year'] = df.set_index('eventDate').index.year
+ df['month'] = df.set_index('eventDate').index.month
+
+ with self.assertRaises(KeyError):
+ df.reset_index().pivot_table(index='year', columns='month',
+ values='badname', aggfunc='count')
+
  def test_agg_over_numpy_arrays(self):
  # GH 3788
  df = pd.DataFrame([[1, np.array([10, 20, 30])],

pandas/tools/pivot.py

@@ -107,6 +107,11 @@ def pivot_table(data, values=None, index=None, columns=None, aggfunc='mean',
  values_multi = False
  values = [values]
 
+ # GH14938 Make sure value labels are in data
+ for i in values:
+ if i not in data:
+ raise KeyError(i)
+
  to_filter = []
  for x in keys + values:
  if isinstance(x, Grouper):