Processing train and test data I have X numpy array as my features and y numpy array as my target. I split both of it into train and test data. From many QnA i have read they only say to preprocess both train and test separately. I assume i only do it to my feature (X) train and test data and not the target (y). Do we also preprocess the target?
Do we also preprocess the target?


Sometimes. The most common example is scaling the target variable for regression, which is beneficial for some algorithms. Another example is when the distribution of the target variable is skewed and is processed into being normally distributed by log-transformation.