On Thu, Nov 12, 2009 at 11:39, Charles R Harris <charlesr.har...@gmail.com> wrote: > > > On Thu, Nov 12, 2009 at 10:32 AM, Christopher Barker <chris.bar...@noaa.gov> > wrote: >> >> David Cournapeau wrote: >> >> > I would love having a core C library of containers - >> >> I'm all for that. However, I think that a very, very common need is >> simply for a growable numpy array. >> >> It seems this would actually be pretty darn easy (again, for someone >> familiar with the code!). >> >> IIUC, it would be exactly like a regular old ndarray, except: >> >> 1) The data block could be larger than the current size of the array: >> - this would require an additional attribute to carry that size >> >> 2) There would be an "append" method, or some other name: >> - this would increase the size of the array, manipulating >> .dimensions, and, if needed, doing a reallocation of the data pointer. >> - This is not very complex code, really, you simply allocate more >> than required, choosing some (user-resettable?) scale: 25% more than >> before, or whatever. re-allocating memory is actually pretty cheap these >> days, so it's not all that critical how you do it. >> >> 3) we'd probably want a .fit() method that would resize the data block >> to fit the current size of the array. >> >> In fact, as I write this, I wonder if these features could simply be >> added to the regular old ndarray -- if not used, they wouldn't be much >> overhead. >> > > I'm rapidly losing interest here. Perhaps you could supply some code > implementing this new array? Why not just a class using an array that > doubles the array size when an index is out of bounds and copies over the > old data. That is pretty much what realloc does. As to python lists, do you > have any benchmarks showing how bad python lists are compared to arrays?
Didn't we already do this? http://www.mail-archive.com/numpy-discussion@scipy.org/msg21010.html -- 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 _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
