grouping a flat list of number by range

[Paddy]

I did a little re-arranging of the generator version:

def interv3(inlist):
    tmp = inlist[0]
    valinc = tmp+1
    for val in inlist[1:]:
        if val != valinc:
            yield [tmp, valinc];
            tmp = val
        valinc = val+1
    yield [tmp, valinc]