# Is LASSO regression implemented in Statsmodels?

I would love to use a linear LASSO regression within statsmodels, so to be able to use the 'formula' notation for writing the model, that would save me quite some coding time when working with many categorical variables, and their interactions. However, it seems like it is not implemented yet in stats models?

• I haven't used statsmodel yet..but I do know that scikit learn has LASSO regression. Would that suit your purpose? Apr 17 '17 at 9:25
• yes scikit-learn would do just as well, I just learnt how to use Patsy to use the 'formula' notation in sciki-learn Apr 17 '17 at 9:44

The question-asker resorted to scikit-learn until now, but statsmodels has just come out with its implementation of Lasso regression. The docs here are pretty self-explanatory and concise.

Ok alternate solution: I can use Patsy with scikit-learn to obtain the same results I would obtain with the formula notation in statsmodels. See code below:

from patsy import dmatrices

# create dummy variables, and their interactions
y, X = dmatrices('outcome ~ C(var1)*C(var2)', df, return_type="dataframe")
# flatten y into a 1-D array so scikit-learn can understand it
y = np.ravel(y)


and I can now use any model implemented in scikit-learn with the usual notations having X as independent variables, and y as dependent one.

http://statsmodels.sourceforge.net/stable/genindex.html