如何从文件名中剪切 tar.gz 扩展名

Question

I have a problem with deleting extension from my filename. I tried to use

os.path.splitext(checked_delivery)[0]

, but it delete only .gz from filename. I need to check if file has extension or it's a directory. I did it using this:

os.path.exists(delivery)

But another problem is, that I can't split it cause of data in it (YYYY.MM.DD). Should I use join() or it is something more attractive instead of tons of methods and ifs?

Answer 1

I propose the following small function:

def strip_extension(fn: str, extensions=[".tar.bz2", ".tar.gz"]):
    for ext in extensions:
        if fn.endswith(ext):
            return fn[: -len(ext)]
    raise ValueError(f"Unexpected extension for filename: {fn}")

assert strip_extension("foo.tar.gz") == "foo"

Answer 2

I propose a generic solution to remove the file extension from the string using the pathlib module. Using the os to manage the paths is not that convenient nowadays, IMO.

import pathlib


def remove_extention(path: pathlib.PosixPath) -> path.PosixPath:
    suffixes = ''.join(path.suffixes)
    return pathlib.Path(str(path).replace(suffixes, ''))

Answer 3

If you know that the extension is always going to be .tar.gz, you can still use split:

In [1]: fname = 'RANDOM_FILE-2017.06.07.tar.gz'

In [2]: '.'.join(fname.split('.')[:-2])
Out[2]: 'RANDOM_FILE-2017.06.07'

From the docstring for os.path.splitext:

"Extension is everything from the last dot to the end, ignoring leading dots. "

In the case of gzipped tarballs, this makes sense anyway, as the file 'FILE.tar.gz' is a gzipped version of the 'FILE.tar', which is presumably a tarball made from file 'FILE'

This is why you would need to use something other than os.path.splitext for this, if what you need is the original filename, without .tar