def strip(strs, fits): strs = list(strs) for idx in range(0, len(strs), 1): if strs[idx] in fits: strs[idx] = None continue break for idx in range(len(strs)-1, -1, -1): if strs[idx] in fits: strs[idx] = None continue break return ''.join([c for c in strs if c is not None])