Python checks whether files and folders exist,

Python checks whether files and folders exist,

1. python checks whether files and folders exist and creates folders
Copy codeThe Code is as follows:
>>> Import OS
>>> OS. path. exists ('d:/assist ')
True
>>> OS. path. exists ('d:/assist/getTeacherList. py ')
True
>>> OS. path. isfile ('d:/assist ')
False
>>> OS. path. isfile ('d:/assist/getTeacherList. py ')
True
>>> OS. makedirs ('d:/assist/set ')
>>> OS. path. exists ('d:/assist/set ')
True

Ii. python checks whether a file exists

Copy codeThe Code is as follows:
Import OS
 
Filename = R'/home/tim/workspace/test.txt'
If OS. path. exists (filename ):
Message = 'OK, the "% s" file exists .'
Else:
Message = "Sorry, I cannot find the" % s "file ."
Print message % filename

Iii. How to Use Python to determine whether a file exists

You can use the OS. path. exists () method to directly determine whether a file exists.

The Code is as follows:
Copy codeThe Code is as follows:
>>> Import OS
>>> OS. path. exists (r'c: \ 1. TXT ')
False
>>>

If the returned value is True or not, False is returned.

Iv. Determine whether a folder exists in python

Copy codeThe Code is as follows:
$ Python
Python 2.7.3 (default, Jan 2 2013, 16:53:07)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> Import OS
>>>
>>>
>>> Tobecheckdir = R'/home/tim/workspace'
>>> OS. path. isdir (tobecheckdir)
True
>>>

5. Check whether the file exists and whether the path is a file in python.

Before writing a file, you usually need to check whether the file path is writable:
Copy codeThe Code is as follows:
From OS import path, access, R_ OK # W_ OK for write permission.

PATH = './file.txt'

If path. exists (PATH) and path. isfile (PATH) and access (PATH, R_ OK ):
Print "File exists and is readable"
Else:
Print "Either file is missing or is not readable"

You can also implement the following method:
Copy codeThe Code is as follows:
Def file_exists (filename ):
Try:
With open (filename) as f:
Return True
Handle t IOError:
Return False

6. python checks whether files and folders exist.

Copy codeThe Code is as follows:
Import OS
OS .path.isfile('test.txt ') # returns False if it does not exist.
OS. path. exists (directory) # If the directory does not exist, False is returned.

VII. OS. path. lexist

And OS. path. lexists (path)
True is also returned for the link file of broken.

8. Determine whether a folder exists through python FTP

How does python determine whether a folder exists? The majority of users gave the answer:
You can use the ftp library. The following is an example of Python core programming:
Copy codeThe Code is as follows:
>>> From ftplib import FTP
>>> F = FTP ('ftp .python.org ')
>>> F. login ('anonus us', 'guido @ python.org ')
'2017 Guest login OK, access restrictions apply .'
>>> F. dir ()

The file does not exist in the dir result.
Or:
Copy codeThe Code is as follows:
Try:
F. retrbinary ('retr % s' % FILE, open (FILE, 'wb '). write)
Failed t ftplib. error_perm:
Print 'error: cannot read file "% s" '% FILE 40 OS. unlink (FILE)

This file cannot be read, nor does it exist.