On Feb 20, 4:55 pm, marwie <mar...@gmx.de> wrote: > Hello, > > I recently read about augmented assignments and that (with l1, l2 > being lists) > > l1.extend(l2) > > is more efficient than > > l1 = l1 + l2 > > because unnecessary copy operations can be avoided. Now my question is > if there's a similar thing for breaking a list into two parts. Let's > say I want to remove from l1 everything from and including position 10 > and store it in l2. Then I can write > > l2 = l1[10:] > del l1[10:] > > But since I'm assigning a slice the elements will be copied.
That's about the best you can do with Python lists. > Basically, I'm looking for something like l1.pop(10,len(l1)) which > returns and removes a whole chunk of data. Is there such a thing (and > if not, why not?) Numpy arrays can share underlying data like that when you take slices. For instance, this probably works the way you want: a = numpy.array([1,2,3,4,5,6]) b = a[:3] c = a[3:] None of the actual data was copied here. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
