Create file but if name exists add number

Question

Does Python have any built-in functionality to add a number to a filename if it already exists?

My idea is that it would work the way certain OS\'s work - if a file

Answer 1

Let's say I already have those files:

This function generates the next available non-already-existing filename, by adding a _1, _2, _3, etc. suffix before the extension if necessary:

import os

def nextnonexistent(f):
    fnew = f
    root, ext = os.path.splitext(f)
    i = 0
    while os.path.exists(fnew):
        i += 1
        fnew = '%s_%i%s' % (root, i, ext)
    return fnew

print(nextnonexistent('foo.txt'))  # foo_3.txt
print(nextnonexistent('bar.txt'))  # bar_1.txt
print(nextnonexistent('baz.txt'))  # baz.txt

Answer 2

recently I encountered the same thing and here is my approach:

import os

file_name = "file_name.txt"
if os.path.isfile(file_name):
    expand = 1
    while True:
        expand += 1
        new_file_name = file_name.split(".txt")[0] + str(expand) + ".txt"
        if os.path.isfile(new_file_name):
            continue
        else:
            file_name = new_file_name
            break