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 is output to a directory where a file of that name already exists, it would append a number or increment it.
I.e: if "file.pdf" exists it will create "file2.pdf", and next time "file3.pdf".
I ended up writing my own simple function for this. Primitive, but gets the job done:
def uniquify(path):
filename, extension = os.path.splitext(path)
counter = 1
while os.path.exists(path):
path = filename + " (" + str(counter) + ")" + extension
counter += 1
return path
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'))
tempfile. The tempfile module takes pains to avoid certain race conditions, security, and denial of service attacks. Using sequential numbering makes the above code vulnerable to a denial of service attack. And I am not entirely sure the above is safe from race conditions or other security risks either.If all files being numbered isn't a problem, and you know beforehand the name of the file to be written, you could simply do:
import os
counter = 0
filename = "file{}.pdf"
while os.path.isfile(filename.format(counter)):
counter += 1
filename = filename.format(counter)
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.
os.path.isfile(fname) logic worked wellrecently 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
Let's say you already have those files:
This function generates the next available non-already-existing filename, by adding a _1, _2, _3, ... 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
Since the tempfile hack A) is a hack and B) still requires a decent amount of code anyway, I went with a manual implementation. You basically need:
I defined a safe_open that can be used just like open:
def iter_incrementing_file_names(path):
"""
Iterate incrementing file names. Start with path and add " (n)" before the
extension, where n starts at 1 and increases.
:param path: Some path
:return: An iterator.
"""
yield path
prefix, ext = os.path.splitext(path)
for i in itertools.count(start=1, step=1):
yield prefix + ' ({0})'.format(i) + ext
def safe_open(path, mode):
"""
Open path, but if it already exists, add " (n)" before the extension,
where n is the first number found such that the file does not already
exist.
Returns an open file handle. Make sure to close!
:param path: Some file name.
:return: Open file handle... be sure to close!
"""
flags = os.O_CREAT | os.O_EXCL | os.O_WRONLY
if 'b' in mode and platform.system() == 'Windows':
flags |= os.O_BINARY
for filename in iter_incrementing_file_names(path):
try:
file_handle = os.open(filename, flags)
except OSError as e:
if e.errno == errno.EEXIST:
pass
else:
raise
else:
return os.fdopen(file_handle, mode)
# Example
with safe_open("some_file.txt", "w") as fh:
print("Hello", file=fh)
I haven't tested this yet but it should work, iterating over possible filenames until the file in question does not exist at which point it breaks.
def increment_filename(fn):
fn, extension = os.path.splitext(path)
n = 1
yield fn + extension
for n in itertools.count(start=1, step=1)
yield '%s%d.%s' % (fn, n, extension)
for filename in increment_filename(original_filename):
if not os.isfile(filename):
break
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.
This function validates if the file name exists using regex expresion and recursion
def validate_outfile_name(input_path):
filename, extension = os.path.splitext(input_path)
if os.path.exists(input_path):
output_path = ""
pattern = '\([0-9]\)'
match = re.search(pattern, filename)
if match:
version = filename[match.start() + 1]
try: new_version = int(version) + 1
except: new_version = 1
output_path = f"{filename[:match.start()]}({new_version}){extension}"
output_path = validate_outfile_name(output_path)
else:
version = 1
output_path = f"{filename}({version}){extension}"
return output_path
else:
return input_path
Here is an answer that does not contain a race condition from checking if the file exists in advance. It caps out at 999 attempts so the program won't hang forever if the file fails to create, the same as a shell usually would.
import os
def create_file_unique(path, read=False, binary=False, min_=1, max_=1000):
mode = ''.join(('x', '+' if read else '', 'b' if binary else ''))
def increment_file_name():
root, ext = os.path.splitext(path)
return (path if num == min_ else '%s (%d)%s' % (root, num, ext
) for num in range(min_, max_))
for i in increment_file_name():
try:
return open(i, mode)
except FileExistsError:
pass
raise IOError('The file %r could not be created uniquely.' % path)
if __name__ == '__main__':
with create_file_unique('unique.txt') as f:
print('Hello World', file=f)
By default, it will open the file with write-only permissions in text mode. Specify read as True for read and write permissions, and binary as True for binary mode. (Note that having read-only permissions would be useless - after all, you just created the file blank!)
Be aware that for the sake of simplicity, this answer (as well as the other answers here) assumes the filename passed in is "bare." That is to say, it will not handle the scenario where the filename passed in already contains a number in parenthesis, like create_file_unique('unique (2).txt'). In that case, this function will add another number on the end, resulting in unique (2) (2).txt. This differs from the typical behaviour of OS functions intended to accomplish this task, like PathYetAnotherMakeUniqueName from the Windows shell, which will check if the filename passed in already contains a number in parenthesis and will update that number in place if it finds one.
If you're willing to forego sequential filenames, you could use NamedTemporaryFile with a prefix, suffix, and deletion turned off, in order to accomplish something similar.
import os
from tempfile import NamedTemporaryFile
def create_file_unique(path, mode='w+b'):
root, ext = os.path.splitext(path)
return NamedTemporaryFile(
delete=False, mode=mode,
prefix=root, suffix=ext, dir=''
)
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
import os
class Renamer():
def __init__(self, name):
self.extension = name.split('.')[-1]
self.name = name[:-len(self.extension)-1]
self.filename = self.name
def rename(self):
i = 1
if os.path.exists(self.filename+'.'+self.extension):
while os.path.exists(self.filename+'.'+self.extension):
self.filename = '{} ({})'.format(self.name,i)
i += 1
return self.filename+'.'+self.extension
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!
def generate_filename(filepath, name="image", ext="jpg"):
files_list = os.listdir(filepath)
file_filter = list(filter(lambda x: x.startswith(name), files_list))
if files_list and file_filter:
latest_file = sorted(file_filter, key=lambda x: os.path.splitext(x)[0].split("_")[-1])[-1]
if latest_file:
filename, ext = os.path.splitext(latest_file)
file, num = filename.rsplit("_", 1)
try:
new_filename = f"{file}_{str(int(num) + 1)}{ext}"
return new_filename
except ValueError:
return f"{name}_0{ext}"
else:
return f"{name}_0.{ext}"
Easy way for create new file if this name in your folder
if 'sample.xlsx' in os.listdir('testdir/'):
i = 2
while os.path.exists(f'testdir/sample ({i}).xlsx'):
i += 1
wb.save(filename=f"testdir/sample ({i}).xlsx")
else:
wb.save(filename=f"testdir/sample.xlsx")
def create_file():
counter = 0
filename = "file"
while os.path.isfile(f"dir/{filename}{counter}.txt"):
counter += 1
print(f"{filename}{counter}.txt")
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
filename_fix_existing(filename)