In article <[EMAIL PROTECTED]>, Erik Max Francis <[EMAIL PROTECTED]> wrote:
> David C. Ullrich wrote: > > > Thanks. I would have guessed that I'd want low-level style code; > > that's the sort of thing I have in mind. In fact the only thing > > that seems likely to come up right now is looping through an > > array of bytes, modifying them. The plan is to use the array > > module first to convert a string or a list to an array, outside > > the accelerated part, then maybe do something like > > > > for j in range(len(bytes)/3): > > g = (bytes[3*j] + bytes[3*j+1] + bytes[3*j+2])/3 > > bytes[3*j] = bytes[3*j+1] = bytes[3*j+2] = g > > If len(bytes) is large, you might want to use `xrange`, too. `range` > creates a list which is not really what you need. I didn't follow the explanation, but I read in the docs that xrange can actually be slower under Psyco. This morning I learned that my guess that array.array was a good idea was correct: When I pass a list of ints to the routine above it gets accelerated by a factor of between 10 and 15, while if I pass an array it's closer to 50. This is so cool. Maybe I already said that. -- David C. Ullrich -- http://mail.python.org/mailman/listinfo/python-list
