On Tue, Nov 7, 2017, 4:58 AM Balazs Pataki <[email protected]> wrote:
> You could also try this, which is a bit more pythonic, also faster. > > def re_sort(to_sort): >> # we need those zeroes so we check how many of them we have >> nr_of_zeroes = to_sort.count(0) >> # list comprehension that gets rid of zeroes >> filtered = [item for item in to_sort if item != 0] >> # we append together the filtered part and inplace add a list of >> zeroes of length nr_of_zeroes >> return filtered + [0]*nr_of_zeroes > > > While this has time complexity of O(n), yours is O(n^2), so the longer > your list gets, the worse your performance gets. > I'm not great at big O notation. Is the original solution suggested to be O(n^2) because of the nested remove(i) call within the loop? Would that have a logarithmic complexity instead because the list becomes shorter everytime it finds a 0 and removes it? Otherwise it would not remove at all for nonzero. And then your solution has two O(n) calls (the count and the list comp) so that is O(n) yea? Then you have the memory complexity of needing to allocate temporary lists for the final nonzero and zero lists. Here is one more approach that uses a sort in place. It has both examples depending on whether you want the nonzero numbers sorted or not. by_nonzero = lambda i: 0 if i else 1 l = [4,0,8,0,0,2,1,-5] l.sort(key=by_nonzero) print l # [4, 8, 2, 1, -5, 0, 0, 0] import sys maxint = sys.maxint by_nonzero = lambda i: i or maxint l = [4,0,8,0,0,2,1,-5] l.sort(key=by_nonzero) print l # [-5, 1, 2, 4, 8, 0, 0, 0] > > On Sunday, November 5, 2017 at 3:07:32 PM UTC+1, Virbhadra Gupta wrote: >> >> >> >> i was trying to sort list by only 0 and other Numbers like [2,0,0,4] to >> [2,4,0,0] >> i come up with this code but in this code variable list is changing. i am >> unable to understand why ? >> >> list = [4,0,0,4] >> >> def re_sort(list): >> count=0 >> tmp_list = list >> print list >> for i in list: >> if not i: >> tmp_list.remove(i) >> count+=1 >> print list >> for n in range(count): >> tmp_list.append(0) >> return tmp_list >> re_sort(list) >> >> ************************ >> re_sort(list) >> [4, 0, 0, 4] >> [4, 0, 4] >> # Result: [4, 0, 4, 0] # >> > -- > You received this message because you are subscribed to the Google Groups > "Python Programming for Autodesk Maya" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/python_inside_maya/700827e3-cb90-4106-8da4-350e08096dbd%40googlegroups.com > <https://groups.google.com/d/msgid/python_inside_maya/700827e3-cb90-4106-8da4-350e08096dbd%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Python Programming for Autodesk Maya" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/python_inside_maya/CAPGFgA1k7yVorfG_sbf2Pj7%3DG4qo5X-A7vhOO0DQZseu%3DxSGjA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
