Issue computing fixed effects

[ijohnsson-chwy]

`import pyfixest as pf

data = pf.get_data()
mod = pf.feols("Y ~ X1 | f1 + f2", data=data)
mod.summary()
mod.fixef()`

gives the error

`---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
Cell In[114], line 6
4 mod = pf.feols("Y ~ X1 | f1 + f2", data=data)
5 mod.summary()
----> 6 mod.fixef()

File /opt/conda/lib/python3.11/site-packages/pyfixest/estimation/feols_.py:1740, in Feols.fixef(self, atol, btol)
1738 res: dict[str, dict[str, float]] = {}
1739 for i, col in enumerate(cols):
-> 1740 variable, level = _extract_variable_level(col)
1741 # check if res already has a key variable
1742 if variable not in res:

File /opt/conda/lib/python3.11/site-packages/pyfixest/utils/dev_utils.py:191, in _extract_variable_level(fe_string)
188 t_match = re.search(t_pattern, fe_string, re.DOTALL)
190 if not c_match or not t_match:
--> 191 raise ValueError(
192 f"feols() failed after regex encountered the following value as a fixed effect:\n {fe_string}."
193 + "\nThis may due to the presence of line separation and/or escape sequences within the string."
194 + " If so, consider recoding the underlying string. Otherwise, please open a PR in the github repo!"
195 )
197 variable = c_match.group(1)
198 level = t_match.group(1)

ValueError: feols() failed after regex encountered the following value as a fixed effect:
C(f1)[0.0].
This may due to the presence of line separation and/or escape sequences within the string. If so, consider recoding the underlying string. Otherwise, please open a PR in the github repo!`

[s3alfisc]

Hi @ijohnsson-chwy , thanks for reporting this!

I cannot reproduce this under pyfixest 0.27:

%load_ext autoreload
%autoreload 2

import pyfixest as pf

data = pf.get_data()
mod = pf.feols("Y ~ X1 | f1 + f2", data=data)
mod.summary()
mod.fixef()

Which version of the package are you running? You can check this by running pip show pyfixest in the command line.

[kassemdana]

I get the same error with pyfixest 0.27

[s3alfisc]

Hi, can you manually downgrade to formulaic < 1.1.0? Ie 1.0.2? This should solve your issue, it's related to a change in formulaic 1.1.0.

[s3alfisc]

I finally managed to reproduce this, btw @ijohnsson-chwy 😅

[kassemdana]

perfect! it worked!