Usage: Enter a key as a number. Click the Next button to perform one comparison. Click the Reset button to start over with a new random list of the specified size (min 3 and max 20). The Custom Input button enables you to enter a custom list.

low: 0

↓

mid: 1

↓

high: 1

↓

Set list size: Key: Next Reset Custom Input

A list is filled with random numbers.

  1  def binarySearch(lst, key):
  2      low = 0
  3      high = len(lst) - 1
  4  
  5      while high >= low:
  6          mid = (low + high) / 2
  7          if key < lst[mid]:
  8              high = mid - 1
  9          elif key == lst[mid]:
 10              return mid
 11          else:
 12              low = mid + 1
 13  
 14      return -low - 1 # Now high < low