create all unique permutations of a word. please comment if you know of more efficient ways to do it.

unique-permutations.py

#!/usr/bin/env python2

import sys
from itertools import permutations

str1 = sys.argv[1]
str2 = int(len(str1))

def uniques(iterable, r=None):
    '''weird behavior in itertools permutations.
    returns same values multiple times in many cases.

    >>> [ ''.join(i) for i in itertools.permutations('to') ]
    ['to', 'ot']
    >>> print(len([ ''.join(i) for i in itertools.permutations('to') ]))
    2
    >>> [ ''.join(i) for i in itertools.permutations('tol') ]
    ['tol', 'tlo', 'otl', 'olt', 'lto', 'lot']
    >>> print(len([ ''.join(i) for i in itertools.permutations('tol') ]))
    6
    >>> [ ''.join(i) for i in itertools.permutations('toll') ] # incorrect
    ['toll', 'toll', 'tlol', 'tllo', 'tlol', 'tllo', 'otll', 'otll', 'oltl',
            'ollt', 'oltl', 'ollt', 'ltol', 'ltlo', 'lotl', 'lolt', 'llto',
            'llot', 'ltol', 'ltlo', 'lotl', 'lolt', 'llto', 'llot']
    >>> print(len([ ''.join(i) for i in itertools.permutations('toll') ])) # incorrect
    24

    this is due to the chosen algorithm (which in many cases makes sense).
    in order to to use it correctly on text, we can store the permutations in a tuple,
    check for multiples and return unique value only. it's certainly not the sexiest
    way in terms of performance but it gets the job done up to a few million iterations
    on commodity hardware.

    $ echo qwertzuiop | wc -m
    11
    $ time ./unique-permutations.py qwertzuiop | wc -l
    3628800

    real    0m2.208s
    user    0m2.221s
    sys     0m0.059s

    $ echo qwertzuiopa | wc -m
    12
    $ time ./unique-permutations.py qwertzuiopa | wc -l
    479001600

    real    5m13.190s
    user    5m15.362s
    sys     0m7.821s

    if you need bigger numbers or more performance, use bigger guns.

    more infos:
    https://docs.python.org/2/library/itertools.html#itertools.permutations
    '''
    existent = tuple()
    for e in permutations(sorted(iterable), r):
        if e > existent:
            existent = e
            yield e

for p in uniques(str1, str2):
    print ''.join(p)

#help(uniques)

$ wget https://gist.githubusercontent.com/heyalexej/2f74a9bda5bceec9ad02/raw/unique-permutations.py -O unique-permutations.py && chmod u+x unique-permutations.py && ./unique-permutations.py test