Python: How to create a unique file name?

If you want to make temporary files in Python, there’s a module called tempfile in Python’s standard libraries. If you want to launch other programs to operate on the file, use tempfile.mkstemp() to create files, and os.fdopen() to access the file descriptors that mkstemp() gives you.

Incidentally, you say you’re running commands from a Python program? You should almost certainly be using the subprocess module.

So you can quite merrily write code that looks like:

import subprocess
import tempfile
import os

(fd, filename) = tempfile.mkstemp()
try:
    tfile = os.fdopen(fd, "w")
    tfile.write("Hello, world!n")
    tfile.close()
    subprocess.Popen(["/bin/cat", filename]).wait()        
finally:
    os.remove(filename)

Running that, you should find that the cat command worked perfectly well, but the temporary file was deleted in the finally block. Be aware that you have to delete the temporary file that mkstemp() returns yourself – the library has no way of knowing when you’re done with it!

(Edit: I had presumed that NamedTemporaryFile did exactly what you’re after, but that might not be so convenient – the file gets deleted immediately when the temp file object is closed, and having other processes open the file before you’ve closed it won’t work on some platforms, notably Windows. Sorry, fail on my part.)

I came across this question, and I will add my solution for those who may be looking for something similar. My approach was just to make a random file name from ascii characters. It will be unique with a good probability.

from random import sample
from string import digits, ascii_uppercase, ascii_lowercase
from tempfile import gettempdir
from os import path

def rand_fname(suffix, length=8):
    chars = ascii_lowercase + ascii_uppercase + digits

    fname = path.join(gettempdir(), 'tmp-'
                + ''.join(sample(chars, length)) + suffix)

    return fname if not path.exists(fname) 
                else rand_fname(suffix, length)

Maybe you need unique temporary file?

import tempfile

f = tempfile.NamedTemporaryFile(mode='w+b', delete=False)

print f.name
f.close()

f is opened file. delete=False means do not delete file after closing.

If you need control over the name of the file, there are optional prefix=... and suffix=... arguments that take strings. See https://docs.python.org/3/library/tempfile.html.

This can be done using the unique function in ufp.path module.

import ufp.path
ufp.path.unique('./test.ext')

if current path exists ‘test.ext’ file. ufp.path.unique function return ‘./test (d1).ext’.

You can use the datetime module

import datetime
uniq_filename = str(datetime.datetime.now().date()) + '_' + str(datetime.datetime.now().time()).replace(':', '.')

Note that:
I am using replace since the colons are not allowed in filenames in many operating systems.

That’s it, this will give you a unique filename every single time.

The uuid module would be a good choice, I prefer to use uuid.uuid4().hex as random filename because it will return a hex string without dashes.

import uuid
filename = uuid.uuid4().hex

The outputs should like this:

>>> import uuid
>>> uuid.uuid()
UUID('20818854-3564-415c-9edc-9262fbb54c82')
>>> str(uuid.uuid4())
'f705a69a-8e98-442b-bd2e-9de010132dc4'
>>> uuid.uuid4().hex
'5ad02dfb08a04d889e3aa9545985e304'  # <-- this one

To create a unique file path if its exist, use random package to generate a new string name for file. You may refer below code for same.

import os
import random
import string

def getUniquePath(folder, filename):    
    path = os.path.join(folder, filename)
    while os.path.exists(path):
         path = path.split('.')[0] + ''.join(random.choice(string.ascii_lowercase) for i in range(10)) + '.' + path.split('.')[1]
    return path

Now you can use this path to create file accordingly.

In case you need short unique IDs as your filename, try shortuuid, shortuuid uses lowercase and uppercase letters and digits, and removing similar-looking characters such as l, 1, I, O and 0.

>>> import shortuuid
>>> shortuuid.uuid()
'Tw8VgM47kSS5iX2m8NExNa'
>>> len(ui)
22

compared to

>>> import uuid
>>> unique_filename = str(uuid.uuid4())
>>> len(unique_filename)
36
>>> unique_filename
'2d303ad1-79a1-4c1a-81f3-beea761b5fdf'