On 08/01/2021 05.52, Bischoop wrote:
> On 2021-01-07, Chris Angelico <ros...@gmail.com> wrote:
>>
>> True. Unfortunately, it doesn't work, so what you'd have is something
>> that can be easily parameterized to not work on other numbers of
>> characters too. :)
>>
>
> My bad is I'm kinda maniac and have to know how to, I know best solution
> itertool but... I just must know, was thinking that studing the itertool
> code would give me an answer but found it's in C.
> Now I try list comprehension for it, so it's another day on it for me.
BTW have you realised a second 'typo' - that there are only 24 letters
in this 'alphabet'?
It is not difficult to parametrise the building of a "password cracking
dictionary"! (NB not same definition as a Python dictionary) Take it one
step (one character) at a time...
We start from our list of "letters". This is every permutation of the
alphabet, taken one at a time. Call it the one_character_list.
[Let's not distract from the problem by arguing about the definition of
"permutation"!]
Next, we'll take the one_character_list and permute that, with each of
our letter[s]. Thus 'a, b, c' expands to 'aa, ab, ac, ... ba, bb, bc,
... ca, cb, cc, ...'.
For every one of the 24 elements of the one_character_list we now have
24 elements in the two_character_list, ie len( two_character_list )
should be 24*24 (== 24**2) and each element should be unique (ie same
rule as a set).
NB above equation varies if the rule for what may be the first character
of a password differs for the rule of which letters/characters may follow!
Similarly, if we take the two_character_list, we can permute that
(again/further) with each letter. Thus 'aaa, aab, aac, ...baa, bab, bac,
...'. Thus, len( three_character_list ) == 24 * 24 * 24 == 24 ** 3 ==
len( two_character_list ) * 24 == len( one_character_list ) * 24 * 24
Carrying-on we can build a "password cracking dictionary" of any length.
NB the three-character_list contains exactly 'what it says on the tin'
(English-English expression meaning that the label is entirely correct).
Thus if the password rules say 'up to three characters in length', then
the password-cracker would have to test each of the three lists in-turn
too look for one-character passwords, then two-character passwords, and
finally three...!
Disclaimers:
Permutations and combinations are an interesting [learning] exercise,
and we're getting used to your preference for step-by-step
experimentation and learning-mastery.
That said, @David is correct - once understood, use the tool! Because
these multiple loops are "expensive" (in terms of execution-time).
Per @Chris and comments above, consider when and where to use
character-strings, tuples, lists, and/or sets - for 'best results'
and/or 'best practice'.
Per @yourself, once you have coded, tested, and debugged a solution
featuring explicit for-loops, it will be a valuable exercise to upgrade
(the code and quite probably the execution speed) using
comprehensions/expressions...
Sample code:
def permute_lists( existing_list:list, expansion_list:list )->list:
'''Expand each of the existing list's elements
with every element of a provided list.
'''
permuted_list = list()
for existing_element in existing_list:
for expansion_element in expansion_list:
permuted_list.append( existing_element + expansion_element )
return permuted_list
# establish character-set to be used
letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
'm', 'n', 'o', 'p', 'r',
's', 't', 'u', 'w', 'q', 'y', 'z']
# taking each of the letters once is the character-set
one_character_list = letters
print( len( one_character_list ) )
print( one_character_list, end="\n" )
# taking the letters two at a time
two_character_list = permute_lists( one_character_list, letters )
print( len( two_character_list ), len( one_character_list ) * len(
letters ) )
print( two_character_list, end="\n" )
# taking the letters three at a time
three_character_list = permute_lists( two_character_list, letters )
print( len( three_character_list ), len( two_character_list ) * len(
letters ) )
print( three_character_list, end="\n" )
--
Regards =dn
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