["python","list","random","performance"]
Create random list of integers in Python

I'd like to create a random list of integers for testing purposes. The distribution of the numbers is not important. The only thing that is counting is time. I know generating random numbers is a time-consuming task, but there must be a better way. Here's my current solution: import random import timeit # Random lists from [0-999] interval print [random.randint(0, 1000) for r in xrange(10)] # v1 print [random.choice([i for i in xrange(1000)]) for r in xrange(10)] # v2 # Measurement: t1 = timeit.Timer('[random.randint(0, 1000) for r in xrange(10000)]', 'import random') # v1 t2 = timeit.Timer('random.sample(range(1000), 10000)', 'import random') # v2 print t1.timeit(1000)/1000 print t2.timeit(1000)/1000 v2 is faster than v1, but it is not working on such a large scale. It gives the following error: ValueError: sample larger than population Is there a fast, efficient solution that works at that scale? Some results from the answer Andrew's: 0.000290962934494 gnibbler's: 0.0058455221653 KennyTM's: 0.00219276118279 NumPy came, saw, and conquered.
It is not entirely clear what you want, but I would use numpy.random.randint: import numpy.random as nprnd import timeit t1 = timeit.Timer('[random.randint(0, 1000) for r in xrange(10000)]', 'import random') # v1 ### Change v2 so that it picks numbers in (0, 10000) and thus runs... t2 = timeit.Timer('random.sample(range(10000), 10000)', 'import random') # v2 t3 = timeit.Timer('nprnd.randint(1000, size=10000)', 'import numpy.random as nprnd') # v3 print t1.timeit(1000)/1000 print t2.timeit(1000)/1000 print t3.timeit(1000)/1000 which gives on my machine: 0.0233682730198 0.00781716918945 0.000147947072983 Note that randint is very different from random.sample (in order for it to work in your case I had to change the 1,000 to 10,000 as one of the commentators pointed out -- if you really want them from 0 to 1,000 you could divide by 10). And if you really don't care what distribution you are getting then it is possible that you either don't understand your problem very well, or random numbers -- with apologies if that sounds rude...