python多线程编程特别适用于完成相互独立的任务，同时进行，相互之间没有依赖性。比如，下面我们介绍的从网站中查询每本书的排名这个任务，就非常适合应用多线程来提升效率。

1 理论分析

单线程情况下，查询n本书的排名，需要执行n次排名查询。
多线程情况下，同时对每一本书的排名进行查询，无需顺序执行。

2 代码实现

2.1 单线程的代码实现`bookrank.py`

#!/usr/bin/env python
# coding=utf-8

# import pdb
from atexit import register
from re import compile
from threading import Thread
from time import ctime
from urllib2 import urlopen as uopen


REGEX = compile('#([\d,]+) in Books')
AMZN = 
ISBNs = {
    '0132269937':'Core Python Programming',
    '0132356139':'Python web Development with Djanjo',
    '0137143419':'Python Fundamentals',
}


def getRanking(isbn):
    page = uopen('%s%s' % (AMZN,isbn))
    data = page.read()
    page.close()
    return REGEX.findall(data)[0]

def _showRanking(isbn):
    print '- %r ranked %s' %(ISBNs[isbn],getRanking(isbn))



def main():
    print 'At', ctime(), 'On Amazon...'
#    pdb.set_trace()
    for isbn in ISBNs:
        _showRanking(isbn)

@register
def _atexit():
    print 'ALL DONE at:', ctime()


if __name__ == '__main__':
    main()

运行结果分析：

Paste_Image.png

单线程用时20s。

2.2 多线程的代码实现 `bookrank_mts.py`

#!/usr/bin/env python
# coding=utf-8

# import pdb
from atexit import register
from re import compile
from threading import Thread
from time import ctime
from urllib2 import urlopen as uopen


REGEX = compile('#([\d,]+) in Books')
AMZN = 
ISBNs = {
    '0132269937':'Core Python Programming',
    '0132356139':'Python web Development with Djanjo',
    '0137143419':'Python Fundamentals',
}


def getRanking(isbn):
    page = uopen('%s%s' % (AMZN,isbn))
    data = page.read()
    page.close()
    return REGEX.findall(data)[0]

def _showRanking(isbn):
    print '- %r ranked %s' %(ISBNs[isbn],getRanking(isbn))



def main():
    print 'At', ctime(), 'On Amazon...'
#    pdb.set_trace()
    for isbn in ISBNs:
        Thread(target=_showRanking, args=(isbn,)).start()

@register
def _atexit():
    print 'ALL DONE at:', ctime()


if __name__ == '__main__':
    main()

Paste_Image.png

多线程用时6s。