>>>import timeit>>> timeit.timeit('"-".join(str(n) for n in range(100))', number=10000)0.3412662749997253>>> timeit.timeit('"-".join([str(n) for n in range(100)])', number=10000)0.2996307989997149>>> timeit.timeit('"-".join(map(str, range(100)))', number=10000)0.24581470699922647