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

This works for me. The initial file name is 0.yml, if it exists, it will add one until meet the requirement

import os
import itertools

def increment_filename(file_name):
    fid, extension = os.path.splitext(file_name)

    yield fid + extension
    for n in itertools.count(start=1, step=1):
        new_id = int(fid) + n
        yield "%s%s" % (new_id, extension)


def get_file_path():
    target_file_path = None
    for file_name in increment_filename("0.yml"):
        file_path = os.path.join('/tmp', file_name)
        if not os.path.isfile(file_path):
            target_file_path = file_path
            break
    return target_file_path

Answer 2

In a way, Python has this functionality built into the tempfile module. Unfortunately, you have to tap into a private global variable, tempfile._name_sequence. This means that officially, tempfile makes no guarantee that in future versions _name_sequence even exists -- it is an implementation detail. But if you are okay with using it anyway, this shows how you can create uniquely named files of the form file#.pdf in a specified directory such as /tmp:

import tempfile
import itertools as IT
import os

def uniquify(path, sep = ''):
    def name_sequence():
        count = IT.count()
        yield ''
        while True:
            yield '{s}{n:d}'.format(s = sep, n = next(count))
    orig = tempfile._name_sequence 
    with tempfile._once_lock:
        tempfile._name_sequence = name_sequence()
        path = os.path.normpath(path)
        dirname, basename = os.path.split(path)
        filename, ext = os.path.splitext(basename)
        fd, filename = tempfile.mkstemp(dir = dirname, prefix = filename, suffix = ext)
        tempfile._name_sequence = orig
    return filename

print(uniquify('/tmp/file.pdf'))

Answer 3

A little bit later but there is still something like this should work properly, mb it will be useful for someone.

You can use built-in iterator to do this ( image downloader as example for you ):

def image_downloader():

        image_url = 'some_image_url'

        for count in range(10):
            image_data = requests.get(image_url).content

            with open(f'image_{count}.jpg', 'wb') as handler:
                handler.write(image_data)

Files will increment properly. Result is:

image.jpg
image_0.jpg
image_1.jpg
image_2.jpg
image_3.jpg
image_4.jpg
image_5.jpg
image_6.jpg
image_7.jpg
image_8.jpg
image_9.jpg

Answer 4

I was trying to implement the same thing in my project but @unutbu's answer seemed too 'heavy' for my needs so I came up with following code finally:

import os
index = ''
while True:
    try:
        os.makedirs('../hi'+index)
        break
    except WindowsError:
        if index:
            index = '('+str(int(index[1:-1])+1)+')' # Append 1 to number in brackets
        else:
            index = '(1)'
        pass # Go and try create file again

Just in case someone stumbled upon this and requires something simpler.

Answer 5

I found that the os.path.exists() conditional function did what I needed. I'm using a dictionary-to-csv saving as an example, but the same logic could work for any file type:

import os 

def smart_save(filename, dict):
    od = filename + '_' # added underscore before number for clarity

    for i in np.arange(0,500,1): # I set an arbitrary upper limit of 500
        d = od + str(i)

        if os.path.exists(d + '.csv'):
            pass

        else:
            with open(d + '.csv', 'w') as f: #or any saving operation you need
                for key in dict.keys():
                    f.write("%s,%s\n"%(key, dictionary[key]))
            break

Note: this appends a number (starting at 0) to the file name by default, but it's easy to shift that around.

Answer 6

I've implemented a similar solution with pathlib:

Create file-names that match the pattern path/<file-name>-\d\d.ext. Perhaps this solution can help...

import pathlib
from toolz import itertoolz as itz

def file_exists_add_number(path_file_name, digits=2):

    pfn = pathlib.Path(path_file_name)
    parent = pfn.parent     # parent-dir of file
    stem = pfn.stem         # file-name w/o extension
    suffix = pfn.suffix     # NOTE: extension starts with '.' (dot)!

    try:
        # search for files ending with '-\d\d.ext'
        last_file = itz.last(parent.glob(f"{stem}-{digits * '?'}{suffix}"))
    except:
        curr_no = 1
    else:
        curr_no = int(last_file.stem[-digits:]) + 1

    # int to string and add leading zeros
    curr_no = str(last_no).zfill(digits)
    path_file_name = parent / f"{stem}-{curr_no}{suffix}"

    return str(path_file_name)

Pls note: That solution starts at 01 and will only find file-pattern containing -\d\d!