Attribute error in Continuous Optimal binning

[villelliv]

I get the following Attribute error:
File "...\Python\Python312\site-packages\optbinning\binning\continuous_binning.py", line 441, in fit
return self._fit(x, y, sample_weight, check_input)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "...\Python\Python312\site-packages\optbinning\binning\continuous_binning.py", line 660, in _fit
n_zeros] = self._fit_prebinning(
^^^^^^^^^^^^^^^^^^^^^
File "...\Python\Python312\site-packages\optbinning\binning\binning.py", line 893, in _fit_prebinning
return self._prebinning_refinement(prebinning.splits, x, y, y_missing,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "...\Python\Python312\site-packages\optbinning\binning\continuous_binning.py", line 855, in _prebinning_refinement
self._max_target_special] = target_info_special_continuous(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "...\Python\Python312\site-packages\optbinning\binning\binning_statistics.py", line 200, in target_info_special_continuous
std_special.append(0)
^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'append'

when using ContinuousOptimalBinning  with special codes as follows:
    optb = ContinuousOptimalBinning(name=factor, dtype='numerical', monotonic_trend='auto_asc_desc',max_n_bins=20,
                                            special_codes={'special_5': -5, 'special_6': -6,
                                                           'special_7': -7, 'special_9': -9})
 The error seems to occur in some cases, for example when no special values are present and only with continuous target. What could be the root cause of this?
 
 Thank you,
 Ville

[guillermo-navas-palencia]

Hi @villelliv. Thanks for notifying this issue. I will look into this.