ValueError: Solver not supported for given penalty (LogisticRegression)

ValueError: logistic solver vs penalty

$ python -c "from sklearn.linear_model import LogisticRegression; LogisticRegression(penalty='l1', solver='lbfgs').fit([[0,1],[1,0],[1,1]],[0,1,0])"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ValueError: Solver lbfgs supports only 'l2' or 'none' penalties.

Why this happens

• Using a solver that doesn’t support the chosen penalty.

Fix

• Use compatible pairs, e.g., penalty='l1' with solver='liblinear' or saga.

Wrong code

LogisticRegression(penalty='l1', solver='lbfgs').fit(X, y)

Fixed code

LogisticRegression(penalty='l1', solver='liblinear').fit(X, y)