How to index 0-d array in Python?

Question

This may be a well-known question stored in some FAQ but i can't google the solution. I'm trying to write a scalar function of scalar argument but allowing for ndarray argument. The function should check its argument for domain correctness because domain violation may cause an exception. This example demonstrates what I tried to do:

import numpy as np
def f(x):
    x = np.asarray(x)
    y = np.zeros_like(x)
    y[x>0.0] = 1.0/x
    return y

print f(1.0)

On assigning y[x>0.0]=... python says 0-d arrays can't be indexed. What's the right way to solve this execution?

Answer 1

This will work fine in NumPy >= 1.9 (not released as of writing this). On previous versions you can work around by an extra np.asarray call:

x[np.asarray(x > 0)] = 0