Array subtraction and/or reshaping

Question

I would like some help with a problem. In Python:

a=array([2,2])
b=ones((2,10))

I would like to know if there is a function that allows me to subtract b-a to have an array of 2x10 full of -1.

I can do it one with 1D arrays, I just wanted to know if it is possible to do with 2D arrays.

Thanks

Answer 1

Add a new dimension to a:

b - a[:,None]

where a[:,None] becomes array([[2], [2]]), a 2x1 array which you can substract from a 2x10 array and get a 2x10 array full of -1.

Answer 2

You want to have an array of 2x10 full of -1.

Why don't you just do like this:

b = np.ones((2, 10)) * -1

array([[-1., -1., -1., -1., -1., -1., -1., -1., -1., -1.],
       [-1., -1., -1., -1., -1., -1., -1., -1., -1., -1.]])