How to remove every other element of an array in python? (The inverse of np.repeat()?)

Question

If I have an array x, and do an np.repeat(x,2), I'm practically duplicating the array.

>>> x = np.array([1,2,3,4])     >>> np.repeat(x, 2) array([1, 1, 2, 2, 3, 3, 4, 4]) 

How can I do the opposite so that I end up with the original array?

It should also work with a random array y:

>>> y = np.array([1,7,9,2,2,8,5,3,4])   

How can I delete every other element so that I end up with the following?

array([7, 2, 8, 3]) 

Answer 1

y[1::2] should do the job. Here the second element is chosen by indexing with 1, and then taken at an interval of 2.