Merging a list of time-range tuples that have overlapping time-ranges

A few ways to make it more efficient, Pythonic:

1. Eliminate the set() construction, since the algorithm should prune out duplicates during in the main loop.
2. If you just need to iterate over the results, use yield to generate the values.
3. Reduce construction of intermediate objects, for example: move the tuple() call to the point where the final values are produced, saving you from having to construct and throw away extra tuples, and reuse a list saved for storing the current time range for comparison.

Code:

def merge(times):
    saved = list(times[0])
    for st, en in sorted([sorted(t) for t in times]):
        if st <= saved[1]:
            saved[1] = max(saved[1], en)
        else:
            yield tuple(saved)
            saved[0] = st
            saved[1] = en
    yield tuple(saved)

data = [
    [(1, 5), (2, 4), (3, 6)],
    [(1, 3), (2, 4), (5, 8)]
    ]

for times in data:
    print list(merge(times))