Need help with python

hey /prog/
Need help with python
I am randomly generating all possible 20 character long strings consisting of 1234567890abcdef, and printing them to a file.
I generate the strings using:

CHARS="abcdef1234567890"
def rand_string(string_length):
        output = ''            
       
        for i in xrange(string_length):
                output += random.choice(CHARS)

Now i need to print rand_string(20) over and over again to an output file, but checking said file for that string, and only printing it if it isn't there yet.

Any thoughts?

are you sure you are supposed to do this? Such a file would have 20 * 16^20 = 24178516392292583494123520 bytes.

Read SICP

You're not returning anything from rand_string

This is the worst brute force attack I've ever seen

I have a thought, why don't you just use crunch which will do the job for you?

Why not modify rand_string to append results to a list, first checking that list to make sure there are no duplicates, then print the contents of the list to a file when finished?

>>1

printed = set()
for _ in xrange(strings_to_print):
    s = rand_string(string_length)
    if s not in printed:
        print s
        printed.add(s)
But the chances to get a collision with 80 bit strings are pretty much negligible, so maybe it's not worth the effort.

Also, use ''.join(random.choice(CHARS) for _ in xrange(string_length)) instead of your silly loop.

Okay I'm a total novice programmer but I'm having a go for the sake of practice.


def random_strings(string_length):
    CHARS = "abcdef1234567890"
    output = []
    while len(output) < 16**string_length:
        string=""
        string.join(random.choice(CHARS) for _ in xrange(string_length))
        if string not in output:
            output.append(string)
    return output

Of course I know this is going to take years to come back at a length of 20 characters, so there must be a smarter way to do it, anyone know what it is?

>>8

Couple of questions, since you seem to know what you're talking about.

If printed is a type set, isn't it redundant to have if s not in printed in there? Because sets don't allow duplicates so it won't get added anyway?

Also, why do you call that loop silly? Isn't ''.join(random.choice(CHARS) for _ in xrange(string_length)) the same loop, just syntactically different?

Excuse my ignorance, like I said I'm a novice.

>>9
Sorry, I don't even know how that code is even supposed to work, I meant to post


def random_strings(string_length):
    CHARS = "abcdef1234567890"
    output = []
    while len(output) < 16**string_length:
        string=""
        for i in xrange(string_length):
            string += random.choice(CHARS)
        if string not in output:
            output.append(string)
    return output

http://en.wikipedia.org/wiki/Permutation

It's gonna be a pretty big file.

#! /usr/bin/env python

import os
import sys

from itertools import product

def main (argv):
    chars  = 'abcdef1234567890'
    length = 20

    if len(argv) < 2:
        print >> sys.stderr, 'usage: %s filename' % (argv[0])
        return 1

    outfile = open(argv[1], 'w')

    for s in product(chars, repeat=length):
        outfile.write(s)
        outfile.write(os.linesep)

    outfile.close()

    return 0

if __name__ == '__main__':
    exit(main(sys.argv))

>>1
Hey OP you're a fucking fag.
head -c 10 /dev/urandom | hexdump -v -e '/1 "%02x"'; echo

>>13
You're the fag, Mr. >>13. Think about it.

>>14
Does your mom know your gay?