Changing file extension in Python

Solution 1:

An elegant way using pathlib.Path:

from pathlib import Path
p = Path('mysequence.fasta')
p.rename(p.with_suffix('.aln'))

Solution 2:

os.path.splitext(), os.rename()

for example:

# renamee is the file getting renamed, pre is the part of file name before extension and ext is current extension
pre, ext = os.path.splitext(renamee)
os.rename(renamee, pre + new_extension)

Solution 3:

import os
thisFile = "mysequence.fasta"
base = os.path.splitext(thisFile)[0]
os.rename(thisFile, base + ".aln")

Where thisFile = the absolute path of the file you are changing

Solution 4:

Starting from Python 3.4 there's pathlib built-in library. So the code could be something like:

from pathlib import Path

filename = "mysequence.fasta"
new_filename = Path(filename).stem + ".aln"

https://docs.python.org/3.4/library/pathlib.html#pathlib.PurePath.stem

I love pathlib :)