The way Python determines whether files and folders exist

This article mainly introduces the python to determine whether files and folders exist methods, this article also explains whether the file or directory of the method, the role of Os.path.lexist, FTP to determine whether the file or directory exists, and other content, the need for friends can refer to the

First, Python to determine whether files and folders exist, create folders

The 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

Second, Python to determine whether the file exists

The 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

Use the Os.path.exists () method to directly determine whether a file exists.

The code is as follows:

The code is as follows:

>>> Import OS

>>> os.path.exists (R ' C:1.txt ')

False

>>>

Returns False if there is a return value of true if it does not exist

Four, Python to determine whether the folder exists

The code is as follows:

$ python

Python 2.7.3 (default, 2 2013, 16:53:07)

[GCC 4.7.2] on linux2

Type ' help ', ' copyright ', ' credits ' or ' license ' for the more information.

>>> Import OS

>>>

>>>

>>> Tobecheckdir = R '/home/tim/workspace '

>>> Os.path.isdir (Tobecheckdir)

True

>>>

Five, Python check if the file exists, and whether the path is a file

You usually need to check that the file path is writable before you write the file:

The 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 isn't not readable '

You can also do this in the following ways:

The code is as follows:

def file_exists (filename):

Try

with open (filename) as F:

Return True

Except IOError:

Return False

Six, Python to determine whether files and folders exist

The code is as follows:

Import OS

Os.path.isfile (' Test.txt ') #如果不存在就返回False

Os.path.exists (directory) #如果目录不存在就返回False

Seven, Os.path.lexist

and os.path.lexists (PATH)

The link file for broken also returns true.

Eight, Python ftp to determine whether the folder exists

How does python determine if a folder exists? The majority of netizens gave the answer:

Using the FTP library, here are some examples of Python core programming:

The code is as follows:

>>> from Ftplib import FTP

>>> f = FTP (' ftp.python.org ')

>>> f.login (' Anonymous ', ' guido@python.org ')

' 230 Guest Login OK, access restrictions apply. '

>>> F.dir ()

There is no such file in the dir result.

Or as follows:

The code is as follows:

Try

F.retrbinary (' RETR%s '% file,open (FILE, ' WB '). Write)

Except Ftplib.error_perm:

print ' Error:cannot read file '%s '% file Os.unlink (file)