从0开始的Python学习016异常

import sys

try:
  a = input('Enter something:')
except(EOFError):
  print('\nWhy did you do an EOF on me ?')
  sys.exit()
except:
  print('\nSome error/exception occurred.')

print('Done')

import sys

try:
  a = input('Enter something:')
except(EOFError):
  print('\nWhy did you do an EOF on me ?')
  sys.exit()
except:
  print('\nSome error/exception occurred.')
else:
  print('no error')

print('Done')

class ShortInputException(Exception):
  def __init__(self,length,atleast):
    Exception.__init__(self)
    self.length = length
    self.atleast = atleast

try:
  s = input('Enter something-->')
  print(len(s))
  if len(s) < 3:
    raise ShortInputException(len(s),atleast = 3)
except(EOFError):
  print('\nWhy did you do an EOF on me ?')
except(ShortInputException) as x:
  print('ShortInputException: The in input was of length %d,\
      was expecting at least %d' % (x.length,x.atleast))
else:
  print('No exception was raised.')

import time

try:
  f = open('poem.txt')
  while True: # our usual file-reading idiom
    line = f.readline()
    if len(line) == 0:
      break
    time.sleep(2)
    print(line)
finally:
  f.close()
  print('Cleaning up...closed the file')