binary search in python

binary_search.py

#!/usr/bin/env python3

from typing import List

def binary_search(arr: List[int], target: int) -> int:
  """
  >>> arr = [3, 6, 12, 18]
  >>> target = 12
  >>> binary_search(arr, target)
  """
  
  low, high = 0, len(arr) - 1
  
  while low <= high:
    mid = low + (high - low) // 2
    
    if arr[mid] == target:
      return mid
     elif arr[mid] < target:
      low = mid + 1
     else:
      high = mid - 1
      
  return -1
  
  
if __name__ == '__main__':
  import doctest
  doctest.testmod()