lorenzo.py

def binarySearch(alist, item):
  first = 0
  last = len(alist)-1
  index = None
  while first<=last and not index:
    midpoint = (first + last)//2
    if alist[midpoint] >= item:
      index  = midpoint
    else:
      if item < alist[midpoint]:
        last = midpoint-1
      else:
        first = midpoint+1
  return index

def searchDateRange(data, initialDate, finalDate):
  i = binarySearch(data, initialDate)
  if not i:
    print "Could not find lower bound."
    return None
  newArray = data[i:len(data)]
  j = binarySearch(newArray, finalDate)
  if not j:
    print "Could not find upper bound"
    return None
  return data[i:j]