Is there a function to extract the extension from a filename?
25 Answers
Yes. Use os.path.splitext
(see Python 2.X documentation or Python 3.X documentation):
>>> import os
>>> filename, file_extension = os.path.splitext('/path/to/somefile.ext')
>>> filename
'/path/to/somefile'
>>> file_extension
'.ext'
Unlike most manual string-splitting attempts, os.path.splitext
will correctly treat /a/b.c/d
as having no extension instead of having extension .c/d
, and it will treat .bashrc
as having no extension instead of having extension .bashrc
:
>>> os.path.splitext('/a/b.c/d')
('/a/b.c/d', '')
>>> os.path.splitext('.bashrc')
('.bashrc', '')
New in version 3.4.
import pathlib
print(pathlib.Path('yourPath.example').suffix) # '.example'
I'm surprised no one has mentioned pathlib
yet, pathlib
IS awesome!
If you need all the suffixes (eg if you have a .tar.gz
), .suffixes
will return a list of them!
For simple use cases one option may be splitting from dot:
>>> filename = "example.jpeg"
>>> filename.split(".")[-1]
'jpeg'
No error when file doesn't have an extension:
>>> "filename".split(".")[-1]
'filename'
But you must be careful:
>>> "png".split(".")[-1]
'png' # But file doesn't have an extension
Also will not work with hidden files in Unix systems:
>>> ".bashrc".split(".")[-1]
'bashrc' # But this is not an extension
For general use, prefer os.path.splitext
With splitext there are problems with files with double extension (e.g. file.tar.gz
, file.tar.bz2
, etc..)
>>> fileName, fileExtension = os.path.splitext('/path/to/somefile.tar.gz')
>>> fileExtension
'.gz'
but should be: .tar.gz
The possible solutions are here
Although it is an old topic, but i wonder why there is none mentioning a very simple api of python called rpartition in this case:
to get extension of a given file absolute path, you can simply type:
filepath.rpartition('.')[-1]
example:
path = '/home/jersey/remote/data/test.csv'
print path.rpartition('.')[-1]
will give you: 'csv'
Surprised this wasn't mentioned yet:
import os
fn = '/some/path/a.tar.gz'
basename = os.path.basename(fn) # os independent
Out[] a.tar.gz
base = basename.split('.')[0]
Out[] a
ext = '.'.join(basename.split('.')[1:]) # <-- main part
# if you want a leading '.', and if no result `None`:
ext = '.' + ext if ext else None
Out[] .tar.gz
Benefits:
- Works as expected for anything I can think of
- No modules
- No regex
- Cross-platform
- Easily extendible (e.g. no leading dots for extension, only last part of extension)
As function:
def get_extension(filename):
basename = os.path.basename(filename) # os independent
ext = '.'.join(basename.split('.')[1:])
return '.' + ext if ext else None
This is a direct string representation techniques : I see a lot of solutions mentioned, but I think most are looking at split. Split however does it at every occurrence of "." . What you would rather be looking for is partition.
string = "folder/to_path/filename.ext"
extension = string.rpartition(".")[-1]
Another solution with right split:
# to get extension only
s = 'test.ext'
if '.' in s: ext = s.rsplit('.', 1)[1]
# or, to get file name and extension
def split_filepath(s):
"""
get filename and extension from filepath
filepath -> (filename, extension)
"""
if not '.' in s: return (s, '')
r = s.rsplit('.', 1)
return (r[0], r[1])
A true one-liner, if you like regex. And it doesn't matter even if you have additional "." in the middle
import re
file_ext = re.search(r"\.([^.]+)$", filename).group(1)
See here for the result: Click Here
try this:
files = ['file.jpeg','file.tar.gz','file.png','file.foo.bar','file.etc']
pen_ext = ['foo', 'tar', 'bar', 'etc']
for file in files: #1
if (file.split(".")[-2] in pen_ext): #2
ext = file.split(".")[-2]+"."+file.split(".")[-1]#3
else:
ext = file.split(".")[-1] #4
print (ext) #5
- get all file name inside the list
- splitting file name and check the penultimate extension, is it in the pen_ext list or not?
- if yes then join it with the last extension and set it as the file's extension
- if not then just put the last extension as the file's extension
- and then check it out
For funsies... just collect the extensions in a dict, and track all of them in a folder. Then just pull the extensions you want.
import os
search = {}
for f in os.listdir(os.getcwd()):
fn, fe = os.path.splitext(f)
try:
search[fe].append(f)
except:
search[fe]=[f,]
extensions = ('.png','.jpg')
for ex in extensions:
found = search.get(ex,'')
if found:
print(found)
# try this, it works for anything, any length of extension
# e.g www.google.com/downloads/file1.gz.rs -> .gz.rs
import os.path
class LinkChecker:
@staticmethod
def get_link_extension(link: str)->str:
if link is None or link == "":
return ""
else:
paths = os.path.splitext(link)
ext = paths[1]
new_link = paths[0]
if ext != "":
return LinkChecker.get_link_extension(new_link) + ext
else:
return ""