Python3 Note

PIP main error : 

cd /usr/bin/pip3
from pip import __main__
if __name__ == '__main__':
      sys.exit(__main__._main())

training set accuracy K selection:

from sklearn.model_selection import train_test_split

X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.33, random_state=42)