Help: Creating condensed expressions

[bearophileHUGS at lycos.com]

This is a first try, is something like this enough for you?


data = """apple1
apple2
apple3_SD
formA
formB
formC
kla_MM
kla_MB
kca_MM""".split()

headtails = {}
for word in data:
    head = word[:-1]
    if head in headtails:
        headtails[head].append(word[-1])
    else:
        headtails[head] = [word[-1]]
for head, tails in sorted(headtails.iteritems()):
    if len(tails) == 1:
        print head + tails[0]
    else:
        print head + "[%s]" % "".join(tails)


Output:
apple[12]
apple3_SD
form[ABC]
kca_MM
kla_M[MB]

It looks only the last letters. It modifies the original order (it
sorts the sequence on the root-word).
If you don't need sorted results you can remove the sorted().

Bye,
bearophile