Use Python recursion to process objects

Among the many Python application techniques, file operations related methods are an important application technology. Here we will introduce Python recursion to understand its role in file operations, hoping to help you.

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Python recursion has two requirements:

Delete all. svn files in a directory and subdirectory

Delete all objects in a folder

In Python, file operations in Python recursion mainly come from the OS module. The main method is as follows:

1. OS. listdir (dirname): List directories and files under dirname
2. OS. getcwd (): Get the current working directory
3. OS. curdir: returns the current directory '.')
4. OS. chdir (dirname): change the working directory to dirname

1. OS. path. isdir (name): determines whether the name is a directory. If the name is not a directory, false is returned.
2. OS. path. isfile (name): determines whether the name is a file. If the name does not exist, false is returned.
3. OS. path. exists (name): determines whether a file or directory name exists.
4. OS. path. getsize (name): Get the file size. If the name is a directory, return 0L

1. OS. path. abspath (name): Obtain the absolute path.
2. OS. path. normpath (path): standard path string format
3. OS. path. split (name): separates file names and directories.
   In fact, if you fully use a directory, it will also separate the last directory as a file name,
   At the same time, it does not determine whether a file or directory exists)
4. OS. path. splitext (): separates file names and extensions
5. OS. path. join (path, name): Connection directory and file name or directory
6. OS. path. basename (path): returns the file name.
7. OS. path. dirname (path): Return file path

1. OS. remove (dir) # dir is the path of the folder or file to be deleted.
2. OS. rmdir (path) # path of the directory to be deleted. It must be noted that,
   The directory deleted using OS. rmdir must be empty; otherwise, the function fails.

Python recursively deletes the svn code in the directory:

 
 

  
  
#! /Usr/bin/env python
  
  
# Coding = UTF-8
  
  
Import sys, OS, stat
  
  
Def walk (path ):
  
  
For item in OS. listdir (path ):
  
  
Subpath = OS. path. join (path, item)
  
  
Mode = OS. stat (subpath) [stat. ST_MODE]
  
  
If stat. S_ISDIR (mode ):
  
  
If item = ". svn ":
  
  
Print "Cleaning % s" % subpath
  
  
Print "% d deleted" % purge (subpath)
  
  
Else:
  
  
Walk (subpath)
  
  
Def purge (path ):
  
  
Count = 0
  
  
For item in OS. listdir (path ):
  
  
Subpath = OS. path. join (path, item)
  
  
Mode = OS. stat (subpath) [stat. ST_MODE]
  
  
If stat. S_ISDIR (mode ):
  
  
Count + = purge (subpath)
  
  
Else:
  
  
OS. chmod (subpath, stat. S_IREAD | stat. S_IWRITE)
  
  
OS. unlink (subpath)
  
  
Count + = 1
  
  
OS. rmdir (path)
  
  
Count + = 1
  
  
Return count
  
  
If len (sys. argv )! = 2:
  
  
Print "Usage: python cleansvn. py path"
  
  
Sys. exit (1)
  
  
Walk (sys. argv [1]) deletes all files and folders in a directory:
  
  
Code
  
  
#! /Usr/bin/env python
  
  
# Coding = UTF-8
  
  
Import OS
  
  
Def delete_all_file (path ):
  
  
"Delete all folers and files"
  
  
If OS. path. isfile (path ):
  
  
Try:
  
  
OS. remove (path)
  
  
Except t:
  
  
Pass
  
  
Elif OS. path. isdir (path ):
  
  
For item in OS. listdir (path ):
  
  
Itemsrc = OS. path. join (path, item)
  
  
Delete_all_file (itemsrc)
  
  
Try:
  
  
OS. rmdir (path)
  
  
Except t:
  
  
Pass
  
  
If _ name _ = "_ main __":
  
  
Dirname = r'f: \ trunk'
  
  
Print delete_all_file (dirname)
 
 

The above is our introduction to Python recursion.