Binary search for michael

binary_search.py

import math

def binary_search(needle, haystack):
  search_index = int(math.floor(len(haystack) / 2))
  test_item = haystack[search_index]

  print "Searching for %d in %s" % (needle, haystack)
  print "Haystack is %d long. First looking at index %d" % (len(haystack),
                                                            search_index)
  print "Item at index %d is %d" % (search_index, haystack[search_index])
  if (test_item != needle and len(haystack) == 1):
      haystack.insert(search_index, needle)
      return search_index
  if (test_item == needle):
      return search_index
  if (test_item < needle):
      return search_index + binary_search(needle, haystack[search_index:])
  if (test_item > needle):
      return binary_search(needle, haystack[:search_index])

haystack = [0, 2, 4, 6, 8, 10, 12, 14, 16, 18]