如何查找Python中是否存在目录

In the os module in Python, is there a way to find if a directory exists, something like:

>>> os.direxists(os.path.join(os.getcwd()), 'new_folder')) # in pseudocode
True/False

You’re looking for os.path.isdir, or os.path.exists if you don’t care whether it’s a file or a directory.

Example:

import os
print(os.path.isdir("/home/el"))
print(os.path.exists("/home/el/myfile.txt"))

So close! os.path.isdir returns True if you pass in the name of a directory that currently exists. If it doesn’t exist or it’s not a directory, then it returns False.

Python 3.4 introduced into the standard library, which provides an object oriented approach to handle filesystem paths. The is_dir() and exists() methods of a Path object can be used to answer the question:

In [1]: from pathlib import Path

In [2]: p = Path('/usr')

In [3]: p.exists()
Out[3]: True

In [4]: p.is_dir()
Out[4]: True

Paths (and strings) can be joined together with the / operator:

In [5]: q = p / 'bin' / 'vim'

In [6]: q
Out[6]: PosixPath('/usr/bin/vim') 

In [7]: q.exists()
Out[7]: True

In [8]: q.is_dir()
Out[8]: False

Pathlib is also available on Python 2.7 via the pathlib2 module on PyPi.

Yes, use os.path.exists().

We can check with 2 built in functions

os.path.isdir("directory")

It will give boolean true the specified directory is available.

os.path.exists("directoryorfile")

It will give boolead true if specified directory or file is available.

To check whether the path is directory;

os.path.isdir("directorypath")

will give boolean true if the path is directory

Yes use os.path.isdir(path)

As in:

In [3]: os.path.exists('/d/temp')
Out[3]: True

Probably toss in a os.path.isdir(...) to be sure.

Just to provide the os.stat version (python 2):

import os, stat, errno
def CheckIsDir(directory):
  try:
    return stat.S_ISDIR(os.stat(directory).st_mode)
  except OSError, e:
    if e.errno == errno.ENOENT:
      return False
    raise

os provides you with a lot of these capabilities:

import os
os.path.isdir(dir_in) #True/False: check if this is a directory
os.listdir(dir_in)    #gets you a list of all files and directories under dir_in

the listdir will throw an exception if the input path is invalid.

#You can also check it get help for you

if not os.path.isdir('mydir'):
    print('new directry has been created')
    os.system('mkdir mydir')

There is a convenient Unipath module.

>>> from unipath import Path 
>>>  
>>> Path('/var/log').exists()
True
>>> Path('/var/log').isdir()
True

Other related things you might need:

>>> Path('/var/log/system.log').parent
Path('/var/log')
>>> Path('/var/log/system.log').ancestor(2)
Path('/var')
>>> Path('/var/log/system.log').listdir()
[Path('/var/foo'), Path('/var/bar')]
>>> (Path('/var/log') + '/system.log').isfile()
True

You can install it using pip:

$ pip3 install unipath

It’s similar to the built-in pathlib. The difference is that it treats every path as a string (Path is a subclass of the str), so if some function expects a string, you can easily pass it a Path object without a need to convert it to a string.

For example, this works great with Django and settings.py:

# settings.py
BASE_DIR = Path(__file__).ancestor(2)
STATIC_ROOT = BASE_DIR + '/tmp/static'

You may also want to create the directory if it’s not there.

Source, if it’s still there on SO.

=====================================================================

On Python ≥ 3.5, use pathlib.Path.mkdir:

from pathlib import Path
Path("/my/directory").mkdir(parents=True, exist_ok=True)

For older versions of Python, I see two answers with good qualities, each with a small flaw, so I will give my take on it:

Try os.path.exists, and consider os.makedirs for the creation.

import os
if not os.path.exists(directory):
    os.makedirs(directory)

As noted in comments and elsewhere, there’s a race condition – if the directory is created between the os.path.exists and the os.makedirs calls, the os.makedirs will fail with an OSError. Unfortunately, blanket-catching OSError and continuing is not foolproof, as it will ignore a failure to create the directory due to other factors, such as insufficient permissions, full disk, etc.

One option would be to trap the OSError and examine the embedded error code (see Is there a cross-platform way of getting information from Python’s OSError):

import os, errno

try:
    os.makedirs(directory)
except OSError as e:
    if e.errno != errno.EEXIST:
        raise

Alternatively, there could be a second os.path.exists, but suppose another created the directory after the first check, then removed it before the second one – we could still be fooled.

Depending on the application, the danger of concurrent operations may be more or less than the danger posed by other factors such as file permissions. The developer would have to know more about the particular application being developed and its expected environment before choosing an implementation.

Modern versions of Python improve this code quite a bit, both by exposing FileExistsError (in 3.3+)…

try:
    os.makedirs("path/to/directory")
except FileExistsError:
    # directory already exists
    pass

…and by allowing a keyword argument to os.makedirs called exist_ok (in 3.2+).

os.makedirs("path/to/directory", exist_ok=True)  # succeeds even if directory exists.

Two things

1. check if the directory exist?
2. if not, create a directory (optional).

import os
dirpath = "<dirpath>" # Replace the "<dirpath>" with actual directory path.

if os.path.exists(dirpath):
   print("Directory exist")
else: #this is optional if you want to create a directory if doesn't exist.
   os.mkdir(dirpath):
   print("Directory created")