[Numpy-discussion] appending extra items to arrays

Robert Kern robert.kern@gmail....
Thu Oct 11 00:10:49 CDT 2007

Anne Archibald wrote:
> On 11/10/2007, Robert Kern <robert.kern@gmail.com> wrote:
>> Appending to a list then converting the list to an array is the most
>> straightforward way to do it. If the performance of this isn't a problem, I
>> recommend leaving it alone.
> Just a speculation:
> Python strings have a similar problem - they're immutable, and so are
> even more resistant to growth than numpy arrays. For those situations
> where you really really want to grow a srting, python provides
> StringIO, where you keep efficiently adding to the string, then
> finalize it to get the real string out. Would something analogous be
> interesting for arrays?

The Python version of StringIO, at least, just keeps a list, too. The primary
benefit of StringIO is that it exposes the file interface. For building up a
string/array, using the list is just as convenient (and for arrays, probably
more convenient given the variety of shapes one might want to build) and at
least as readable.

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco

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