Creating dynamic array in class [python] -

i've written own list class wraps list-like array type. array has fixed capacity , when array full want capacity double automatically. example, if base capacity 5 when array full , item added, doubles capacity 10 before adding item.

here's code:

from referential_array import build_array  class list:      def __init__(self,capacity):         assert capacity >0, "capacity cannot negative"         self.count = 0         self._array = build_array(capacity)         self.capacity = capacity      def append(self,item):         has_space_left = not self.is_full()         if has_space_left:             self._array[self.count] = item             self.count+=1         else:                                      #issue here             create_more_space = list.__init__(self,capacity*2) #if list full, capacity *2             self.count+=1  if __name__== "__main__":     mylist = list(6)     mylist.append(4)     mylist.append(7)     mylist.append(1)     mylist.append(3)     mylist.append(2)     mylist.append(17)     mylist.append(18)     mylist.append(20) 

below, first specify size 6. go ahead append more 6 items. right, when python sees there no longer space, capacity doubled , hence 18 , 20 can appended well.

i'm getting error saying capacity not defined @ append function. output i'm trying is:

4 7 1 3 2 17 18 20 

the error because members of object in python must accessed self reference:

create_more_space = list.__init__(self, self.capacity * 2) 

i'm not sure why you're doing since built-in python list type has functionality, i'll assume learning. in case, suggest pulling resizing out separate method can called constructor , append. also, current set lose contents of array when capacity changes (because you'll assigning new array on top of old one). e.g.

new_array = build_array(capacity) new_array[0:len(self._array)] = self._array self._array = new_array