Getting 'ValueError: shapes not aligned' on SciKit Linear Regression

Question

Quite new to SciKit and linear algebra/machine learning with Python in general, so I can\'t seem to solve the following:

I have a training set and a test set of data, co

Answer 1

This works for me:
Initially, I was getting this error message:

shapes (15754,3) and (4, ) not aligned 

I found out that, I was creating a model using 3 variables in my train data. But what I add constant X_train = sm.add_constant(X_train) the constant variable is automatically gets created. So, in total there are now 4 variables.
And when you test this model by default the test variable has 3 variables. So, the error gets pops up for dimension miss match.
So, I used the trick that creates a dummy variable for y_test also.

`X_test = sm.add_constant(X_test)`

Though this a useless variable, but this solves all the issue.