Programming challenges: Binary Search

binary-search.py

def binarySearch(array, target):
  # Array has to be sorted in order to check surrounding elements
  left = 0
  right = len(array) - 1
while left <= right:
    mid = (left + right)
    guess = array[mid]
if guess == target:
return mid
if guess > target:
      right = mid - 1 # Set new range starting from midpoint
else:
      left = mid + 1 # Set new range from midpoint
return -1