Merge Numpy structured arrays

merge_structured_arrays.py

import numpy as np

def merge_structured_arrays(array1, array2):
    n1 = len(array1)
    n2 = len(array2)
    array_out = array1.copy()
    array_out.resize(n1 + n2)
    array_out[n1:] = array2
    return array_out

a = np.array(zip([1,2,3],['a','b','c']), dtype=[('col1', int), ('col2', 'S1')])
b = np.array(zip([4,5,6],['d','e','f']), dtype=[('col1', int), ('col2', 'S1')])

c = merge_structured_arrays(a, b)

print c['col1']
print c['col2']