% python -mtimeit '[x for x in xrange(1000)]'
10000 loops, best of 3: 70.2 usec per loop
% python -mtimeit 'for x in xrange(1000): pass'
10000 loops, best of 3: 29 usec per loop
% python -mtimeit '[x for x in xrange(100000)]'
100 loops, best of 3: 7.03 msec per loop
% python -mtimeit 'for x in xrange(100000): pass'
100 loops, best of 3: 2.5 msec per loop