Silly idea but, as you say, the decision is out of you hands :-(

Set up the four sets already shuffled then make an array of references to them. Then create another array with a guaranteed one from each set (0 .. 3) then a random selection of four more from any set. Then shuffle the order. Finally, build the password by concatenating random letters from the sets in the already shuffled order.

knoppix@Microknoppix:~$ perl -MList::Util=shuffle -Mstrict -wE '
my @lc  = shuffle q{a} .. q{z};
my @uc  = shuffle q{A} .. q{Z};
my @dig = shuffle q{0} .. q{9};
my @oth = shuffle qw{ ! " £ $ % ^ & * _ - + = @ ~ };
my @all = \ ( @lc, @uc, @dig, @oth );

my @order = ( 0 .. 3 );
push @order, int rand 4 for 1 .. 4;
@order = shuffle @order;

my $passwd = q{};
$passwd .= $all[ $_ ]->[ rand @{ $all[ $_ ] } ] for @order;

say $passwd;'
E5yR=$%£
knoppix@Microknoppix:~$

[download]

Runs of this have produced &D0%@nn%, F9@F=Rc1, S~j@3WgG, 633P£m!T and o8S4pl!! so, as long as there is no stipulation barring repeated characters, this seems to work.

I hope this is useful.

Update: If repeated characters are not wanted then you can use splice to remove the chosen character from the array so it can't be re-used.

...
$passwd .= splice @{ $all[ $_ ] }, rand @{ $all[ $_ ] }, 1
   for @order;
...

[download]

Cheers,

JohnGG

In reply to Re: Handling elements of an array of array references, where the function calls for an array? by johngg
in thread Handling elements of an array of array references, where the function calls for an array? by desertrat

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