**Question:**

Write a binary search function that searches an item in a sorted list. The function should return the index of elements to be searched in the list.

**Hints:**

- Use if/elif to deal with conditions.

**Solution:**

import math def bin_search(li, element): bottom = 0 top = len(li)-1 index = -1 while top>=bottom and index==-1: mid = int(math.floor((top+bottom)/2.0)) if li[mid]==element: index = mid elif li[mid]>element: top = mid-1 else: bottom = mid+1 return index li=[2,5,7,9,11,17,222] print bin_search(li,11) print bin_search(li,12)