shelve模块理解

import shelve
import sys
def store_person(db):
    pid = input("Enter  unique ID mnumber:")
    person = {}
    person[‘name‘] = input("Enter name:")
    person[‘age‘] = input("Enter age:")
    person[‘phone‘] = input("Enter phone number:")
    db[pid] = person

def lookup_perosn(db):
    pid = input("Enter ID number:")
    field = input("What would you like to know? (name,age,phone)")
    filed = field.strip().lower()
    print(field.capitalize() + ‘:‘,db[pid][field])

def print_help():
    print("The available commons are:")
    print("store:Looks up a person from ID number")
    print("lookup:Looks up a person from ID number")
    print("quit:save changes and exit")
    print("?:Print this message")

def enter_command():
    cmd = input("Enter command(? for help):")
    cmd = cmd.strip().lower()
    return cmd

def main():
    database = shelve.open(‘testdata.dat‘)
    try:
        while True:
            cmd = enter_command()
            if cmd == ‘store‘:
                store_person(database)
            elif cmd == ‘lookup‘:
                lookup_perosn(database)
            elif cmd == ‘?‘:
                print_help()
            elif cmd == ‘quit‘:
                return
    finally:
        database.close()
if __name__ == ‘__main__‘:
    main()