Best way to generate random file names in Python

Question

In Python, what is a good, or the best way to generate some random text to prepend to a file(name) that I\'m saving to a server, just to make sure it does not overwrite. Tha

Answer 1

Python has facilities to generate temporary file names, see http://docs.python.org/library/tempfile.html. For instance:

In [4]: import tempfile

Each call to tempfile.NamedTemporaryFile() results in a different temp file, and its name can be accessed with the .name attribute, e.g.:

In [5]: tf = tempfile.NamedTemporaryFile()
In [6]: tf.name
Out[6]: 'c:\\blabla\\locals~1\\temp\\tmptecp3i'

In [7]: tf = tempfile.NamedTemporaryFile()
In [8]: tf.name
Out[8]: 'c:\\blabla\\locals~1\\temp\\tmpr8vvme'

Once you have the unique filename it can be used like any regular file. Note: By default the file will be deleted when it is closed. However, if the delete parameter is False, the file is not automatically deleted.

Full parameter set:

tempfile.NamedTemporaryFile([mode='w+b'[, bufsize=-1[, suffix=''[, prefix='tmp'[, dir=None[, delete=True]]]]]])

it is also possible to specify the prefix for the temporary file (as one of the various parameters that can be supplied during the file creation):

In [9]: tf = tempfile.NamedTemporaryFile(prefix="zz")
In [10]: tf.name
Out[10]: 'c:\\blabla\\locals~1\\temp\\zzrc3pzk'

Additional examples for working with temporary files can be found here

Answer 2

If you need no the file path, but only the random string having predefined length you can use something like this.

>>> import random
>>> import string

>>> file_name = ''.join(random.choice(string.ascii_lowercase) for i in range(16))
>>> file_name
'ytrvmyhkaxlfaugx'

Answer 3

You could use the UUID module for generating a random string:

import uuid
filename = str(uuid.uuid4())

This is a valid choice, given that an UUID generator is extremely unlikely to produce a duplicate identifier (a file name, in this case):

Only after generating 1 billion UUIDs every second for the next 100 years, the probability of creating just one duplicate would be about 50%. The probability of one duplicate would be about 50% if every person on earth owns 600 million UUIDs.

Answer 4

I personally prefer to have my text to not be only random/unique but beautiful as well, that's why I like the hashids lib, which generates nice looking random text from integers. Can installed through

pip install hashids

Snippet:

import hashids
hashids = hashids.Hashids(salt="this is my salt", )
print hashids.encode(1, 2, 3)
>>> laHquq

Short Description:

Hashids is a small open-source library that generates short, unique, non-sequential ids from numbers.

Answer 5

import uuid
   imageName = '{}{:-%Y%m%d%H%M%S}.jpeg'.format(str(uuid.uuid4().hex), datetime.now())

Answer 6

a common approach is to add a timestamp as a prefix/suffix to the filename to have some temporal relation to the file. If you need more uniqueness you can still add a random string to this.

import datetime
basename = "mylogfile"
suffix = datetime.datetime.now().strftime("%y%m%d_%H%M%S")
filename = "_".join([basename, suffix]) # e.g. 'mylogfile_120508_171442'