import re, os
strs = ['/home/me/data/dataset/images/dark-side_23----83971436re.jpg',
            '/home/me/data/dataset/images/medium-side_23---83971436re.jpg',
            '/home/me/data/dataset/images/others_23---83971436re.jpg',
            '/home/me/data/dataset/images/light-side_23---83971436re.jpg']
rx = re.compile(r'^(?:(?:dark|medium)-)?(.+)_\d+---.*\.jpg$')
for s in strs:
	m = rx.search(os.path.basename(os.path.normpath(s)))
	if m:
		print(m.group(1))