Python使用shelve模块实现简单数据存储的方法

#!/usr/bin/pythonimport sys, shelvedef store_person(db):  """  Query user for data and store it in the shelf object  """  pid = raw_input('Enter unique ID number:')  person = {}  person['name'] = raw_input('Enter name:')  person['age'] = raw_input('Enter age:')  person['phone'] = raw_input('Enter phone number:')  db[pid] = persondef lookup_person(db):  """  Query user for ID and desired field,   and fetch the corresponding data   from the shelf object  """  pid = raw_input('Enter unique ID number:')  temp = db[pid]  field = raw_input('Please enter name, age or phone:')  field.strip().lower()  print field.capitalize() + ': ', temp[field]def print_help():  print 'The avaliable commands are:'  print 'store  :Stores infomation about a person'  print 'lookup  :Looks up a person form ID number'  print 'quit   :Save changes and exit'  print '?    :Prints this message'def enter_command():  cmd = raw_input('Enter command(? for help):')  cmd = cmd.strip().lower()  return cmddef main():  database = shelve.open('database')  # database stores in current directory  try:    while True:      cmd = enter_command()      if cmd == 'store':        store_person(database)      elif cmd == 'lookup':        lookup_person(database)      elif cmd == '?':        print_help()      elif cmd == 'quit':        return  finally:    database.close()    # Close database in any conditionif __name__ == '__main__':  main()