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

问题:

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]) 

回答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) 

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