binary_search_class.py

import math

def search(l, term, offset=0):
    # find the middle
    # find length of list and divide by two
    list_len = len(l)
    if list_len <= 0:
        return None
    middle = math.floor(list_len / 2)

    # print(l, term, middle)
    if l[middle] == term:
        # print("Found it! ", term, middle)
        return middle + offset
    elif l[middle] > term:
        # discard right
        return search(l[:middle], term)
    elif l[middle] < term:
        # discard left
        return search(l[middle+1:], term, middle+1)

    # print("Didn't find anything ...")
    return None


print(search([1,2,3], 2))
print(search([1, 2, 3, 4, 5], 7))
print(search([1, 2, 3, 4, 5, 6, 7, 8], 7))
print(search([1, 3, 5, 7, 9, 11, 13, 15, 17, 19], 5))