I found an answer to this over on Stackoverflow. http://stackoverflow.com/questions/919369/resize-ctypes-array
On Thu, May 28, 2009 at 1:25 AM, Scott Sibley <sisib...@gmail.com> wrote: > I'd like to resize a ctypes array. As you can see, ctypes.resize doesn't > work like it could. I can write a function to resize an array, but I wanted > to know some other solutions to this. Maybe I'm missing some ctypes trick or > maybe I simply used resize wrong. The name c_long_Array_0 seems to tell me > this may not work like I want. What is resize meant for? > > >>> from ctypes import * > >>> c_int * 0 > <class '__main__.c_long_Array_0'> > > >>> intType = c_int * 0 > >>> foo = intType() > >>> foo > <__main__.c_long_Array_0 object at 0xb7ed9e84> > >>> foo[0] > Traceback (most recent call last): > > > File "<stdin>", line 1, in <module> > > IndexError: invalid index > >>> resize(foo, sizeof(c_int * 1)) > > >>> foo[0] > Traceback (most recent call last): > > > File "<stdin>", line 1, in <module> > > IndexError: invalid index > >>> foo > <__main__.c_long_Array_0 object at 0xb7ed9e84> > > > Maybe go with something like: > > >>> ctypes_resize = resize > >>> def resize(arr, type): > > ... tmp = type() > ... for i in range(len(arr)): > > ... tmp[i] = arr[i] > ... return tmp > ... > ... > >>> listType = c_int * 0 > >>> list = listType() > >>> list = resize(list, c_int * 1) > > >>> list[0] > 0 > >>> > > > But that's ugly passing the type instead of the size. It works for its > purpose and that's it. > >
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