n_things at a time

sliding_window.py

from collections import deque, Counter
from typing import Iterable, Callable

def sliding_window(someiterable: Iterable, n: int, returnable: Callable = ''.join): 
    """
    generates an n element sliding window one element 
    at a time in whatever type you want returned
    returnable could be tuple or list
    """
    n_things = deque()
    
    for thing in someiterable: 
         n_things.append(thing) 
         if len(n_things)<n:
             continue 
         elif len(n_things)>n: 
             n_things.popleft() 
         yield returnable(n_things)
              
Counter(sliding_window("CGGAGGACTCTAGGTAACGC", n=3))