import difflib
def find_common(seq):
last = None
new_seq = []
for word in seq:
if not last:
last = word
continue
slices = difflib.SequenceMatcher(None, last, word).get_matching_blocks()
new_seq.append(last[:slices[0].size])
last = None
return new_seq
>>> find_common(lst)
['DS4700_',
'FAS_8200_initiator',
'FirstClass_8200_',
'HP3parInf_',
'HUS_CL',
'HUS_new_CL',
'NetApp_8200_',
'StorwizeAdd_p',
'Storwize_p',
'fas2650_']