Python学习（关于一个简单的通讯录）

   总觉用bash在一些事上有些力不从心，很大程度上是自己水平有限阿。这是一个学习python原因。曾经看过有人这么说过：学习一门编程语言不是说你一定能把它用得多么得炉火纯青，至少那能给你对一个问题的一种不同思考方式。


#!/usr/bin/python

# A simple phone book. Use the struct of dictionary

import pickle
import os


Datastring = {}

# open the data file.
if os.path.exists('data.txt'):
    data = open('data.txt','r+')            # 'r+' open a file but don't clear it.
else:
    data = open('data.txt','w+')            # 'w+' open a file and clear it. 'r+' and 'w+' both open
                                            # a file with Write and read.
string = data.read()
if len(string) == 0:
    print 'The file is empty'
else:
    data.seek(0)        # change the location of the file.
    Datastring = pickle.load(data)
    data.seek(0)
    data.write('')
    data.flush()

# The main menu.
print ' '*16,'*'*35
print """
            What do you want to do?

            1. Join a new name.
            2. Find a man.
            3. Modify a record.
            4. Delete one.
            5. Show all.
            6. exit."""

# The function Join.

def Join():
    print 'Input the name: '
    name = raw_input()
    while True:
        print 'Input the phone: '
        phone = raw_input()
        if phone.isdigit():
            break
    Datastring[name] = phone

# The function Find()

def Find():
    print 'Input the name you want to search:'
    name = raw_input()
    if name in Datastring:
        print '''
            Find:
            Name:%s
            Phone:%s'''%(name,Datastring[name])
    else:
        print 'Not found.'

# The function Show().

def Show():
    print '*'*60
    print 'All people:'
    D_sort = sorted(Datastring.iteritems(),key=lambda d:d[0])
    for p in range(len(D_sort)):
        print 'Name:%s\t\tPhone:%s'%(D_sort[p][0],D_sort[p][1])
    print 'Over.'
    print '*'*60

# The function Modify().

def Modify():
    print 'Input the name that you want to modify:'
    name = raw_input()
    if name in Datastring:
        while True:
            print 'Input the phone:'
            phone = raw_input()
            if phone.isdigit():
                Datastring[name] = phone
                break
    else:
        print 'Wrong name'

# The function Delete().

def Delete():
    print 'Input the name that you want to delete.'
    name = raw_input()
    if name in Datastring:
        Datastring.pop(name)
        print 'Done it.'
    else:
        print 'Not found.'


# The main block.
while True:
    print "You're choice: