@@ -80,6 +80,39 @@ def binary_search_std_lib(sorted_collection, item):
 return index
 return None
 
+def binary_search_by_recursion(sorted_collection, item, left, right):
+
+"""Pure implementation of binary search algorithm in Python by recursion
+
+Be careful collection must be sorted, otherwise result will be
+unpredictable
+First recursion should be started with left=0 and right=(len(sorted_collection)-1)
+
+:param sorted_collection: some sorted collection with comparable items
+:param item: item value to search
+:return: index of found item or None if item is not found
+
+Examples:
+>>> binary_search_std_lib([0, 5, 7, 10, 15], 0)
+0
+
+>>> binary_search_std_lib([0, 5, 7, 10, 15], 15)
+4
+
+>>> binary_search_std_lib([0, 5, 7, 10, 15], 5)
+1
+
+>>> binary_search_std_lib([0, 5, 7, 10, 15], 6)
+
+"""
+midpoint = left + (right - left) // 2
+
+if sorted_collection[midpoint] == item:
+return midpoint
+elif sorted_collection[midpoint] > item:
+return binary_search_by_recursion(sorted_collection, item, left, right-1)
+else:
+return binary_search_by_recursion(sorted_collection, item, left+1, right)
 
 def __assert_sorted(collection):
 """Check if collection is sorted, if not - raises :py:class:`ValueError`