rename - Changing file extension in Python

Question

Suppose from index.py with CGI, I have post file foo.fasta to display file. I want to change foo.fasta's file extension to be foo.aln in display file. How can I do it?

Answer 1

An elegant way using pathlib.Path:

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