Get the largest factor a number that's less than a threshold. Useful for finding the best number for breaking a list up into groups of equal size.

largest_factor.py

import math

""" 
Get the largest factor a number that's less than a threshold. Useful for finding the 
best number for breaking a list up into groups of equal size.
"""
def largest_factor(num, cur=1, factor=1, max_size=10):
    factor = math.ceil(float(num) / cur)
    if factor > max_size:
        return best_factor(arr, cur + 1, int(factor), max_size)
    else:
        return int(factor)