I know that this question is asked many times on this website. But I found that they missed an important point: only file extension with one period was taken into consider like *.png *.mp3, but how do I deal with these filename with two period like .tar.gz.
The basic code is:
filename = '/home/lancaster/Downloads/a.ppt'
extention = filename.split('/')[-1]
But obviously, this code do not work with the file like a.tar.gz.
How to deal with it? Thanks.
You can now use Path from pathlib. It has many features, one of them is suffix:
>>> from pathlib import Path
>>> Path('my/library/setup.py').suffix
'.py'
>>> Path('my/library.tar.gz').suffix
'.gz'
>>> Path('my/library').suffix
''
If you want to get more than one suffix, use suffixes:
>>> from pathlib import Path
>>> Path('my/library.tar.gar').suffixes
['.tar', '.gar']
>>> Path('my/library.tar.gz').suffixes
['.tar', '.gz']
>>> Path('my/library').suffixes
[]
Path from pathlib documentation, and it told me to use .ext . This kept failing and eventually I learned of .suffix. Not sure if the first documentation was for an older version of the Path() library?
pathlib introduced in Python 3.4, make sure you're not looking at Python 2 docs.Here is a in build module in os. More about os.path.splitext.
In [1]: from os.path import splitext
In [2]: file_name,extension = splitext('/home/lancaster/Downloads/a.ppt')
In [3]: extension
Out[1]: '.ppt'
If you have to fine the extension of .tar.gz,.tar.bz2 you have to write a function like this
from os.path import splitext
def splitext_(path):
for ext in ['.tar.gz', '.tar.bz2']:
if path.endswith(ext):
return path[:-len(ext)], path[-len(ext):]
return splitext(path)
Result
In [4]: file_name,ext = splitext_('/home/lancaster/Downloads/a.tar.gz')
In [5]: ext
Out[2]: '.tar.gz'
Edit
Generally you can use this function
from os.path import splitext
def splitext_(path):
if len(path.split('.')) > 2:
return path.split('.')[0],'.'.join(path.split('.')[-2:])
return splitext(path)
It will work for all extensions.
Working on all files.
In [6]: inputs = ['a.tar.gz', 'b.tar.lzma', 'a.tar.lz', 'a.tar.lzo', 'a.tar.xz','a.png']
In [7]: for file_ in inputs:
file_name,extension = splitext_(file_)
print extension
....:
tar.gz
tar.lzma
tar.lz
tar.lzo
tar.xz
.png
/home/lancaster/Downloads/a.tar.gz['tar.gz', 'tar.lzma', 'tar.lz', 'tar.lzo', 'tar.xz', etc...] into my code? There must be many extension like this.
split then him, and his code works well.The role of a file extension is to tell the viewer (and sometimes the computer) which application to use to handle the file.
Taking your worst-case example in your comments (a.ppt.tar.gz), this is a PowerPoint file that has been tar-balled and then gzipped. So you need to use a gzip-handling program to open it. Using PowerPoint or a tarball-handling program wouldn't work. OK, a clever program that knew how to handle both .tar and .gz files could understand both operations and work with a .tar.gz file - but note that it would do that even if the extension was simply .gz.
The fact that both tar and gzip add their extensions to the original filename, rather than replace them (as zip does) is a convenience. But the base name of the gzip file is still a.ppt.tar.
os.path.splitext('/path/to/your/file') If you need a one line code you can use something like (os.path.splitext('path/to/file.ext')[1]).split('.')[1]Simplest One:
import os.path
print os.path.splitext("/home/lancaster/Downloads/a.ppt")[1]
# '.ppt'
One possible way is:
tmp_ext = filename.split('.')[1:]Result is a list = ['tar', 'gz']
extention = ".".join(tmp_ext)Result is your extension as string = 'tar.gz'
Update: Example:
>>> test = "/test/test/test.tar.gz"
>>> t2 = test.split(".")[1:]
>>> t2
['tar', 'gz']
>>> ".".join(t2)
'tar.gz'
>>> import os
>>> import re
>>> filename = os.path.basename('/home/lancaster/Downloads/a.ppt')
>>> extensions = re.findall(r'\.([^.]+)', basename)
['ppt']
>>> filename = os.path.basename('/home/lancaster/Downloads/a.ppt.tar.gz')
>>> extensions = re.findall(r'\.([^.]+)', basename)
['ppt','tar','gz']
with re.findall and python 3.6
filename = '/home/Downloads/abc.ppt.tar.gz'
ext = r'\.\w{1,6}'
re.findall(f'{ext}\\b | {ext}$', filename, re.X)
['.ppt', '.tar', '.gz']
filename = '/home/lancaster/Downloads/a.tar.gz'
extention = filename.split('/')[-1]
if '.' in extention:
extention = extention.split('.')[-1]
if len(extention) > 0:
extention = '.'+extention
print extention
extensionis actually storing the complete filename, it does the same thing regardless of the type of extension.import os;os.path.basename('/home/lancaster/Downloads/a.ppt')gzand nottar.gz. So this question comes down to finding substrings ".tar.gz" etc, in the file names. If you see Rahul's edit, you will find that this is true.a.pptthe default filename will bea.ppt.tar.gz, so there will be more disturbances. Please take this into consider.a.tar.gztoa.tar(2).gz, I cannot open it properly, so the extension istar.gz.