np.vectorized example

In [1]: import numpy as np

In [2]: def myfunc(a,b):
   ...:     if a > b:
   ...:         return a+b
   ...:     else:
   ...:         return float(a) / float(b)
   ...:

In [3]: vfunc = np.vectorize(myfunc)

In [4]: vfunc([4,1,2,3],[1,2,3,4])
Out[4]: array([5, 0, 0, 0])

In [5]: vfunc([0,1,2,3],[1,2,3,4])
Out[5]: array([ 0.        ,  0.5       ,  0.66666667,  0.75      ])

In [6]: vfunc2 = np.vectorize(myfunc, otypes=[np.float])

In [7]: vfunc2([4,1,2,3],[1,2,3,4])
Out[7]: array([ 5.        ,  0.5       ,  0.66666667,  0.75      ])

In [8]: vfunc2([0,1,2,3],[1,2,3,4])
Out[8]: array([ 0.        ,  0.5       ,  0.66666667,  0.75      ])