Python:文件操作技巧(File operation)
读写文件
#
! /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
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
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
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
+
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[
-
]
==
""
:
tmp
=
l[
-
]
else
:
tmp
=
l[
-
]
return
fullpath[0:len(fullpath)
-
len(tmp)
-
]
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)
+
:]
mainLogic()
资源参考:
资源参考:
你可以在这里看到更多的api解释,感谢该作者: http://www.cnpython.org/docs/200/p_119.html