Python 3 教程二:文件和路径访问[转]

1 遍历文件夹和文件

import  os import  os.path #  os,os.path里包含大多数文件访问的函数,所以要先引入它们. #  请按照你的实际情况修改这个路径 rootdir  =   " d:/download " for  parent, dirnames, filenames  in  os.walk(rootdir):     # case 1:      for  dirname  in  dirnames:         print  ( " parent is: "   +  parent)         print  ( " dirname is: "   +  dirname)     # case 2      for  filename  in  filenames:         print  ( " parent is: "   +  parent)         print  ( " filename with full path : "   +  os.path.join(parent, filename)) ''' 知识点:    * os.walk返回一个三元组.其中dirnames是所有文件夹名字(不包含路径),filenames是所有文件的名字(不包含路径).parent表示父目录.    * case1 演示了如何遍历所有目录.    * case2 演示了如何遍历所有文件.    * os.path.join(dirname,filename) : 将形如"/a/b/c"和"d.java"变成/a/b/c/d.java". '''

 

 

2 分割路径和文件名

 

import  os.path # 常用函数有三种:分隔路径,找出文件名.找出盘符(windows系统),找出文件的扩展名. # 根据你机器的实际情况修改下面参数. spath = " D:/download/repository.7z " #  case 1: p,f = os.path.split(spath); print ( " dir is: " + p) print ( " file is: " + f) #  case 2: drv,left = os.path.splitdrive(spath); print ( " driver is: " + drv) print ( " left is: " + left) #  case 3: f,ext = os.path.splitext(spath); print ( " f is: " + f) print ( " ext is: " + ext) '''     知识点:    这三个函数都返回二元组.    * case1 分隔目录和文件名    * case2 分隔盘符和文件名    * case3 分隔文件和扩展名 '''

总结:5个函数

os.walk(spath) os.path.split(spath) os.path.splitdrive(spath) os.path.splitext(spath) os.path.join(path1,path2)

 

3 实战:文件备份小程序

 

import  os import  shutil import  datetime ''' 作用：将目录备份到其他路径。实际效果：假设给定目录"/media/data/programmer/project/python" ，备份路径"/home/diegoyun/backup/“ ，则会将python目录备份到备份路径下，形如：/home/diegoyun/backup/yyyymmddHHMMSS/python/xxx/yyy/zzz..用法:更改这两个参数.backdir:备份目的地.copydirs:想要备份的文件夹. ''' def  mainLogic():     # add dirs you want to copy     backdir = " d:\\test "      print (backdir)    copydirs = []    copydirs.append( " d:\\temp " );     # copydirs.append("d:\\test");              print ( " Copying files  =================== " )    start = datetime.datetime.now()     # gen a data folder for backup     backdir = os.path.join(backdir,start.strftime( " %Y-%m-%d " ))     # print("backdir is:"+backdir)         kc = 0     for  d  in  copydirs:        kc = kc + copyFiles(d,backdir)    end = datetime.datetime.now()     print ( " Finished! =================== " )     print ( " Total files :  "   +  str(kc) )     print ( " Elapsed time :  "   +  str((end - start).seconds) + "  seconds " ) def  copyFiles(copydir,backdir):    prefix = getPathPrefix(copydir)     # print("prefix is:"+prefix )        i = 0     for  dirpath,dirnames,filenames  in  os.walk(copydir):         for  name  in  filenames:            oldpath = os.path.join(dirpath,name)            newpath = omitPrefix(dirpath,prefix)             print ( " backdir is: " + backdir )                       newpath = os.path.join(backdir,newpath)             print ( " newpath is: " + newpath)             if  os.path.exists(newpath) != True:                os.makedirs(newpath)              newpath = os.path.join(newpath,name)             print ( " From: " + oldpath + "  to: " + newpath)            shutil.copyfile(oldpath,newpath)            i = i + 1      return  i     def  getPathPrefix(fullpath):     # Giving /media/data/programmer/project/ , get the prefix      # /media/data/programmer/     l = fullpath.split(os.path.sep)     # print(str(l[-1]=="")          if  l[ - 1 ] == "" :        tmp = l[ - 2 ]     else :        tmp = l[ - 1 ]     return  fullpath[0:len(fullpath) - len(tmp) - 1 ] def  omitPrefix(fullpath,prefix):     # Giving /media/data/programmer/project/python/tutotial/file/test.py ,      # and prefix is Giving /media/data/programmer/project/,      # return path as python/tutotial/file/test.py      return  fullpath[len(prefix) + 1 :]mainLogic()

 

来自:http://www.cnitblog.com/yunshichen/archive/2009/04/01/55931.html

转载于:https://www.cnblogs.com/aoogur/archive/2009/04/09/1432387.html