[Numpy-discussion] Concatenating string arrays

Thomas Robitaille thomas.robitaille@gmail....
Wed Mar 18 14:49:31 CDT 2009


>> import numpy as np
>> arr1 = np.array(['a','b','c'])
>> arr2 = np.array(['d','e','f'])
>>
>> I would like to produce a third array that would contain
>> ['ad','be','cf']. Is there an efficient way to do this? I could do
>> this element by element, but I need a faster method, as I need to do
>> this on arrays with several million elements.
>
>>>> arr1 = np.array(['a','b','c'])
>>>> arr2 = np.array(['d','e','f'])
>>>> arr3 = np.zeros(6, dtype='|S1')
>>>> arr3[::2] = arr1
>>>> arr3[1::2] = arr2
>>>> arr3.view(dtype='|S2')
> array(['ad', 'be', 'cf'],
>       dtype='|S2')
>
> Does this help?

This works wonderfully - thanks!

Tom



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