Python 3 教程二:文件,目录和路径

1 文件夹和文件遍历

import  osimport  os.path#  os,os.path包含大多数文件访问函数，所以首先引入它们.#  请根据您的实际情况修改此路径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返回三元组，其中dirnames是所有文件夹的名称(不包括路径)，filenames是所有文件的名称(不包括路径).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# 有三种常用函数：分隔路径，找出文件名，找出盘符(windows系统)，找出文件的扩展名.# 根据您机器的实际情况修改以下参数.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 复制文件

import  shutilimport  osimport  os.pathsrc = " d:\\download\\test\myfile1.txt "dst = " d:\\download\\test\myfile2.txt "dst2 = " d:/download/test/测试文件夹.txt "dir1 = os.path.dirname(src)print ( " dir1 %s " % dir1)if (os.path.exists(src) == False):    os.makedirs(dir1)       f1 = open(src, " w " )f1.write( " line a\n " )f1.write( " line b\n " )f1.close()shutil.copyfile(src, dst)shutil.copyfile(src, dst2)f2 = open(dst, " r " )for  line  in  f2:     print (line)f2.close()# 测试复制文件夹树try :    srcDir = " d:/download/test "    dstDir = " d:/download/test2 "     # 如果dstdir已经存在，所以shutil.copytree方法会报错！     # 这也意味着你不能直接使用DD:作为目标路径.    shutil.copytree(srcDir, dstDir)except  Exception as err:     print  (err)    '''    知识点:    * shutil.copyfile:如何复制文件    * os.path.exists:如何判断文件夹是否存在    * shutil.copytree:目录树怎样复制？    '''

总结:4个函数

os.path.dirname(path)

os.path.exists(path)

shutil.copyfile(src, dst)

shutil.copytree(srcDir, dstDir)

4 实战:文件备份小程序:文件备份

import os

import shutil

import datetime

'''

功能：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“/备份路径”home/diegoyun/backup/“ ，

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: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  fileames:            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()

5 资源：详细说明方法