Python list set value at index if index does not exist

Question

Is there a way, lib, or something in python that I can set value in list at an index that does not exist? Something like runtime index creation at list:

l =          


        

Answer 1

There isn't a built-in, but it's easy enough to implement:

class FillList(list):
    def __setitem__(self, index, value):
        try:
            super().__setitem__(index, value)
        except IndexError:
            for _ in range(index-len(self)+1):
                self.append(None)
            super().__setitem__(index, value)

Or, if you need to change existing vanilla lists:

def set_list(l, i, v):
      try:
          l[i] = v
      except IndexError:
          for _ in range(i-len(l)+1):
              l.append(None)
          l[i] = v