How to remove nth element in all numpy arrays in a numpy array?

Question

Similar to this, I am curious how to remove specific elements from every numpy array in a numpy array. My data is given in form of X below. I think this should work:

X = [[x1 x2 ... xn] [x1 x2 ... xn] ... [x1 x2 ... xn]]
X.shape
(n,|x|)

Y=numpy.delete(X[:],1)

I would think that Y should now be:

Y = [[x1 x3 ... xn] [x1 x3 ... xn] ... [x1 x3 ... xn]]

where Y.shape should equal (n-1,|y|=|x|), but it is not. What am I failing to grasp? My intention is to be able to remove all x2's (low correlation variable) in every array in X in order to send to a decision tree regressor. It would be even better if I could do this:

index = [ 1 3 7]
Y=numpy.delete(X[:],index)

which works if X is not a 'nested' numpy array. refer to response in link for:

array([1, 2, 3, 4, 5, 6, 7, 8, 9])

index
[2, 3, 6]

new_a = np.delete(a, index)

new_a
array([1, 2, 5, 6, 8, 9])

Answer 1

You need to apply np.delete along an axis. Please refer to the third example in the documentation.

Y = np.delete(X, 1, axis=1)