Randomize a string input into all possibilities

Question

I need help making a program that takes a string using args and randomizes it into every possibility. The program's results would then be saved into a text file provided by the user when executing the program.

Answer 1

If you need all of the possible permutations in a random order, then I would suggest building then shuffling a list:

from itertools import permutations
from random import shuffle

def shuffled_permutations(s):
    perms = list(permutations(s)) # create all permutations
    shuffle(perms) # shuffle the list randomly
    return ["".join(p) for p in perms] # rebuild strings and return

Applying this function:

>>> shuffled_permutations("ABC")
['BCA', 'CBA', 'BAC', 'ABC', 'ACB', 'CAB']

If you don't really need the permutations in a random order (i.e. you just want to know what they all are), it is much more efficient to use permutations directly, e.g.

for p in permutations(s):

Note that, for a string len(s) == n, the length of all permutations is n! (e.g. for n == 5, (5 * 4 * 3 * 2 * 1) == 120); this gets long pretty fast (there are 3,628,800 permutations of my user name, for example).

Answer 2

Call this function:

def permutations(word):
    if len(word) == 1:
        return [word]

    perms = permutations(word[1:])
    char = word[0]
    result = []

    for perm in perms:
        for i in range(len(perm) + 1):
            result.append(perm[:i] + char + perm[i:])
    return result