pytion学习1

个人感觉学习一门新语言，简单的语法懂一点足矣。接下来就是编程。读懂别人程序的每一句，理解每一句的意义。

#Filename:MyAddressBook.py

import cPickle as p

import os

#Class Item

class Item:

    def __init__(self,name,age,gender):

        self.name = name

        self.age = age

        self.gender = gender

#the main menu of address book   

def menu():

    '''the main menu of address book'''

    print ''

    print '1.Insert an item'

    print '2.Delete an item'

    print '3.Modify an item'

    print '4.Display all items'

    print '5.Sort all items'

    print '6.Exit the program'

    print 'What do you want to do?'

    

#initialization of system, load the member list

def begin():

    '''initialization of system, load the member list'''

    global itemlist

    if os.path.exists('memberlist.data') == True:#to judge whether the file exists

        listfile = file('memberlist.data','r')

        if len(listfile.read())!=0:#to judge whether the file is empty

            itemlist = p.load(listfile)        

        listfile.close()

#exitance of system, store the menber list

def end():

    '''exitance of system, store the menber list'''

    global itemlist

    listfile = file('memberlist.data','w+')

    p.dump(itemlist,listfile)

    listfile.close()

#insert an item into the member list   

def insert():

    '''insert an item into the member list'''

    name = raw_input('Enter name:')

    age = int(raw_input('Enter age:'))

    gender = raw_input('Enter gender:')

    item = Item(name,age,gender)

    global itemlist

    itemlist.append(item)

#print an item

def output(item):

    '''print an item'''

    print '%-15s%-5d%s'%(item.name,item.age,item.gender)

#print all items       

def display():

    '''print all items'''

    global itemlist

    l = len(itemlist)

    print 'name           age  gender'

    for i in range(0,l):

        output(itemlist[i])

    print ''

#delete an item by name from member list

def delete():

    '''delete an item by name from member list'''

    name = raw_input('Enter the name you want to delete:')

    global itemlist

    l = len(itemlist)

    for i in range(0,l):

        if (itemlist[i].name == name):

            itemlist.pop(i)

#update an item

def update(item):

    '''update an item'''

    item.name = raw_input('Enter name:')

    item.age = int(raw_input('Enter age:'))

    item.gender = raw_input('Enter gender:')

#update an item's information by name 

def modify():

    '''update an item's information by name'''

    name = raw_input('Enter the name you want to modify:')

    global itemlist

    l = len(itemlist)

    for i in range(0,l):

        if (itemlist[i].name == name):

            update(itemlist[i])

    print 'Update done!'

#sort all items by name

def sort():

    global itemlist

    itemlist.sort(None,key = lambda item:item.name)

#Here are the scripts

itemlist = [] #Notice here!!!

begin()

while True:

    menu()

    sel = int(raw_input())

    if sel == 1:

        insert()

    elif sel == 2:

        delete()

    elif sel == 3:

        modify()

    elif sel == 4:

        display()

    elif sel == 5:

        sort()

    else:

        break

end()

print 'Good Bye!'