lst = ['Item_has_was_updated_May_2010', 'Item_updated_Apr_2011',
    'Item_got_updated_Sept_2011']
month = 'Sep'
year = '2012'
for s in lst:
    list = s.split('_')
list[-2:] = month, year
r = ''
for a in list:
    r = r + '%s_' % a
r = r[:-1]
print(r)
Заменить элементы в списке, python