How to vectorize a function which contains an if statement?

Question

Let's say we have the following function:

def f(x, y):
    if y == 0:
        return 0
    return x/y

This works fine with scalar values. Unfortunately when I try to use numpy arrays for x and y the comparison y == 0 is treated as an array operation which results in an error:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-13-9884e2c3d1cd> in <module>()
----> 1 f(np.arange(1,10), np.arange(10,20))

<ipython-input-10-fbd24f17ea07> in f(x, y)
      1 def f(x, y):
----> 2     if y == 0:
      3         return 0
      4     return x/y

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

I tried to use np.vectorize but it doesn't make a difference, the code still fails with the same error. np.vectorize is one option which gives the result I expect.

The only solution that I can think of is to use np.where on the y array with something like:

def f(x, y):
    np.where(y == 0, 0, x/y)

which doesn't work for scalars.

Is there a better way to write a function which contains an if statement? It should work with both scalars and arrays.