原理先获取所有文件，然后统计每个文件中代码的行数，最后将行数相加，思路很简单。

import os
import os.path
import time
rootdir = '文件路径'
filelists = []

#遍历文件
def getFile(rootdir):
    global filelists
    for parent,dirnames,filenames in os.walk(rootdir):
        for dirname in dirnames:
            getFile(os.path.join(parent,dirname)) #嵌套
        for filename in filenames:
            #print "filename is:"+ filename  
            filelists.append(os.path.join(parent,filename))

#统计一个文件的行数
def countLine(fname):
    count = 0
    for file_line in open(fname).xreadlines():
        if file_line != '' and file_line != '\n': #过滤掉空行
            count += 1
    print fname + '.....' , count
    return count

if __name__ == '__main__' :
    startTime = time.clock()
    getFile(rootdir)
    totalline = 0
    for filelist in filelists:
        totalline = totalline + countLine(filelist)
    print 'totalline:',totalline
    print 'done:%0.2f second' % (time.clock() - startTime)