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python 文件操作技巧
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下一篇 2012-03-21 23:40:38
/ 个人分类:开发代码
#获回文件的列表
def fileList(self,filePath):
li=''
li2=[]
li=os.listdir(filePath)
for a in li:
li2.append(filePath+'\\'+a)
return li2
读写文件(转)
#! /usr/bin/python
# -*- coding: utf8 -*-
spath="D:/download/baa.txt"
f=open(spath,"w") # Opens file for writing.Creates this file doesn't exist.
f.write("First line 1.\n")
f.writelines("First line 2.")
f.close()
f=open(spath,"r") # Opens file for reading
for line in f:
print("每一行的数据是:%s"%line)
f.close()
'''
知识点: 如何读写文件
'''
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".
'''
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)
复制文件
import shutil
import os
import os.path
src="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,那么shutil.copytree方法会报错!
#这也意味着你不能直接用d: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:如何复制目录树
'''
总结:4个函数
- os.path.dirname(path)
- os.path.exists(path)
- shutil.copyfile(src, dst)
- shutil.copytree(srcDir, dstDir)
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()
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