The idea of binary search is to use the information that the array is sorted.
Time complexity is O(log n)
Typical implementation:
def binary_search(array, search_item):
left = 0
right = len(array) - 1
while left <= right:
mid = (left + right) // 2
if array[mid] < search_item:
left = mid + 1
elif array[mid] == search_item:
return mid
else:
right = mid - 1