# OPTION 1
import os
name = os.path.basename('/root/dir/sub/file.ext').split(".")[0]        # returns >file<

# OPTION 2
from pathlib import Path
Path('/root/dir/sub/file.ext').stem        # returns >file<
# Note that if your file has multiple extensions .stem will only remove the last extension.
# For example, Path('file.tar.gz').stem will return 'file.tar'.