import bisect
import random
import sys

HAYSTACK = [1, 4, 5, 6, 8, 12, 15, 20, 21, 23, 23, 26, 29, 30]
NEEDLES = [0, 1, 2, 5, 8, 10, 22, 23, 29, 30, 31]

ROW_FMT = '{0:2d} @ {1:2d} {2}{0:<2d}'


def demo(bisect_fn):
 for needle in reversed(NEEDLES):
 position = bisect_fn(HAYSTACK, needle) # <1>
 offset = position * ' |' # <2>
 print(ROW_FMT.format(needle, position, offset)) # <3>


def grade(score, breakpoints=[60, 70, 80, 90], grades='FDCBA'):
 i = bisect.bisect(breakpoints, score)
 return grades[i]


if __name__ == '__main__':

 if sys.argv[-1] == 'left': # <4>
 bisect_fn = bisect.bisect_left
 else:
 bisect_fn = bisect.bisect

 print('DEMO: ', bisect_fn.__name__) # <5>
 print('haystack ->', ' '.join('%2d' % n for n in HAYSTACK))
 demo(bisect_fn)

 print([grade(score) for score in [33, 99, 77, 70, 89, 90, 100]])

 SIZE = 7
 random.seed(1729)
 my_list = []
 for i in range(SIZE):
 new_item = random.randrange(SIZE * 2)
 bisect.insort(my_list, new_item)
 print("%2d ->" % new_item, my_list)