[Tutor] A file containing a string of 1 billion random digits.

[Richard D. Moores]

On Sun, Jul 18, 2010 at 11:07, bob gailer <bgailer at gmail.com> wrote:

> Check this out:
>
> import random, time
> s = time.time()
> cycles = 1000
> d = "0123456789"*100
> f = open("numbers.txt", "w")
> for i in xrange(n):
>  l = []
>  l.extend(random.sample(d, 1000))
>  f.write(''.join(l))
> f.close()
> print time.time() - s
>
> 1 million in ~1.25 seconds
>
> Therefore 1 billion in ~21 minutes. 3 ghz processor 2 g ram.
>
> Changing length up or down seems to increase time.

Putting "cycles" where you have "n",  I used

import random, time
s = time.time()
cycles = 1000000
d = "0123456789"*100
f = open("/p31working/Data/1billion_digits_rand_num_Gailor.txt", "w")
for i in range(cycles):
    l = []
    l.extend(random.sample(d, 1000))
    f.write(''.join(l))
f.close()
print(time.time() - s)

to get 1 billion random digits into a file in 932 seconds (15.6
minutes).  <http://tutoree7.pastebin.com/Ldh6SX3q>, which uses Steve
D'Aprano's random_digits function, took 201 seconds (3.35 minutes).

Still, I understand yours, and not his (the return line). I'd never
noticed random.sample() before, nor tried out extend() on a list.  So
thanks, Bob.

Dick