slicing

In [4]:
print(X_train[:, 0]) # Extract the 1st coordinate (indexed by 0) of all elements (:) in the array X_train
[ 1.   2.   3.   5.5  6.   7. ]
In [5]:
print(X_train[:, 1]) # Extract the 2nd coordinate (indexed by 1) of all elements (:) in the array X_train
[ 1.   2.5  1.2  6.3  9.   6. ]