Ah, sure, sure, that's true. I guess the broader point is that there's no reason to artificially impose the constraint that numbers can't be repeated: in fact it hurts you in terms of security..
Kris On Wed, Jun 19, 2013 at 8:43 AM, Michael Banzon <[email protected]> wrote: > My point was simply that if you want me to select a random number, but > hands me of list of numbers I'm not allowed to pick, it can't really > be random. If you limit the length of the number (this is programming > - there is always a limit) there is a maximum of how many "random" > numbers I can give you ;-) > > On Wed, Jun 19, 2013 at 2:25 PM, Kristopher Micinski > <[email protected]> wrote: >> That's not true, it can still be random: just over a different state >> space. (In particular [0-9]^n \ {alpha^n | any character is repeated >> in alpha}) >> >> OP: you could pull out a statistics book and read about random events, >> how to generate them using coins, etc... But the easiest way is to >> generate a random number, add it to the list if it's not already in >> the list, etc... The uniformity argument works based on the invariant >> that at each stage the next number you choose to "fix" the rest of >> your choices is random, hence the distribution remains random. >> >> # let assemble_random_nums len = >> let rand () = (Random.int 9) + 1 in >> let rec h l = function >> | 0 -> l >> | i -> let r = rand () in if (List.mem r l) then (h l i) else (h >> (r::l) (i-1)) >> in >> h [] len;; >> val assemble_random_nums : int -> int list = <fun> >> # assemble_random_nums 4;; >> - : int list = [1; 8; 3; 9] >> # assemble_random_nums 4;; >> - : int list = [2; 9; 5; 4] >> # assemble_random_nums 4;; >> >> Kris >> >> On Wed, Jun 19, 2013 at 7:03 AM, Michael Banzon <[email protected]> wrote: >>> First: This isn't really a question related to Android development. >>> >>> Second: Random unique numbers between 1 and 9 (including both >>> extremes) is a set of 9 numbers (I really hope that we are talking >>> about integers and not real/floating point numbers). >>> >>> Third: If you request a unique sequence of numbers 1 to 9 it can't be >>> random as it would include a check for uniqueness that would remove >>> some degree of randomness. >>> >>> On Wed, Jun 19, 2013 at 11:56 AM, vamshi ch <[email protected]> wrote: >>>> Hi All, >>>> >>>> In my application i want to generate random numbers between 1 to 9 and >>>> that is unique. once i get the random number that should not be repeated >>>> for >>>> any one, any where and for me also. it's similar to OTP(one time password) >>>> but some time OTP will be repeated and that is alphanumerical but in my >>>> case >>>> that should not be happen and i need numbers only. >>>> >>>> Please can you tell me what is the approach to achieve it. Please help out >>>> of this.. >>>> >>>> >>>> Please share the code if you have any regarding this.. >>>> >>>> -- >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Android Developers" group. >>>> To post to this group, send email to [email protected] >>>> To unsubscribe from this group, send email to >>>> [email protected] >>>> For more options, visit this group at >>>> http://groups.google.com/group/android-developers?hl=en >>>> --- >>>> You received this message because you are subscribed to the Google Groups >>>> "Android Developers" group. >>>> To unsubscribe from this group and stop receiving emails from it, send an >>>> email to [email protected]. >>>> For more options, visit https://groups.google.com/groups/opt_out. >>>> >>>> >>> >>> >>> >>> -- >>> Michael Banzon >>> http://michaelbanzon.com/ >>> >>> -- >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Android Developers" group. >>> To post to this group, send email to [email protected] >>> To unsubscribe from this group, send email to >>> [email protected] >>> For more options, visit this group at >>> http://groups.google.com/group/android-developers?hl=en >>> --- >>> You received this message because you are subscribed to the Google Groups >>> "Android Developers" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to [email protected]. >>> For more options, visit https://groups.google.com/groups/opt_out. >>> >>> >> >> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Android Developers" group. >> To post to this group, send email to [email protected] >> To unsubscribe from this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/android-developers?hl=en >> --- >> You received this message because you are subscribed to the Google Groups >> "Android Developers" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> > > > > -- > Michael Banzon > http://michaelbanzon.com/ > > -- > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Android Developers" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > > -- -- You received this message because you are subscribed to the Google Groups "Android Developers" group. 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