Pythonic way to convert a list of integers into a string of comma-separated ranges

Question

I have a list of integers which I need to parse into a string of ranges.

For example:

 [0, 1, 2, 3] -> \"0-3\"
 [0, 1, 2, 4, 8] -> \"0-2,4,8\"
         


        

Answer 1

how about this mess...

def rangefy(mylist):
    mylist, mystr, start = mylist + [None], "", 0
    for i, v in enumerate(mylist[:-1]):
            if mylist[i+1] != v + 1:
                    mystr += ["%d,"%v,"%d-%d,"%(start,v)][start!=v]
                    start = mylist[i+1]
    return mystr[:-1]