As far as I can see it, it isn’t covered in the indexing, slicing and iterating scipy tutorial, so let me ask it here:
Say I’ve
x = np.array([[1,2],[3,4],[5,6],[7,8],[9,0]]) x: array([[1, 2], [3, 4], [5, 6], [7, 8], [9, 0]])
How do I slice the array in order get both the first and last rows:
y: array([[1, 2], [3, 4], [7, 8], [9, 0]])
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Answer
I don’t know if there’s a slick way to do that. You could list the indices explicitly, of course:
>>> x[[0,1,-2,-1]] array([[1, 2], [3, 4], [7, 8], [9, 0]])
Or use r_
to help, which would probably be more convenient if we wanted more rows from the head or tail:
>>> x[np.r_[0:2, -2:0]] array([[1, 2], [3, 4], [7, 8], [9, 0]])