Hello, I found this strange: python -mtimeit "sum(int(L) for L in xrange(3000))" 100 loops, best of 3: 5.04 msec per loop python -mtimeit "import itertools; sum(itertools.imap(int, xrange(3000)))" 100 loops, best of 3: 3.6 msec per loop I thought the two constructs could achieve the same speed. -- Giovanni Bajo