On Tue, Mar 10, 2009 at 07:23:56PM -0400, Tim Gales wrote:
> md5(uniqid(rand(), true))
Though MD5 collisions are possible, so I wouldn't count on that always
resulting in a unique id.
--Dan
--
T H E A N A L Y S I S A N D S O L U T I O N S C O M P A N Y
data intensive web a
On Wed, Mar 11, 2009 at 6:16 PM, John Campbell wrote:
> On Wed, Mar 11, 2009 at 5:01 PM, Fernando Gabrieli
> wrote:
>> dont forget that md5($anyString) can return two hashes with the same value
>> (if you have a db with 1,000,000 entries using this, it may happen)
>
> The odds of an MD5 collisio
On Wed, Mar 11, 2009 at 5:01 PM, Fernando Gabrieli wrote:
> dont forget that md5($anyString) can return two hashes with the same value
> (if you have a db with 1,000,000 entries using this, it may happen)
The odds of an MD5 collision with 1,000,000 entries is
0.0001%
That
dont forget that md5($anyString) can return two hashes with the same value
(if you have a db with 1,000,000 entries using this, it may happen)
best,
fernando
On Wed, Mar 11, 2009 at 5:12 AM, Artur Marnik wrote:
> Joey Derrico wrote:
>
>> One possibility would be to make a DB table with 2 column
On Mon, Mar 9, 2009 at 9:56 PM, chad qian wrote:
> Hi,
> I need to generate random 8-digit numbers continuously.And no
> duplication among all those numbers.In other word,every single 8-digit
> number must be unique.How to do php programming?
Just to give a little different answer from what peopl
Joey Derrico wrote:
One possibility would be to make a DB table with 2 columns. One where
each row has a value from through , and the other
column marked as for used. When you need to generate the random number
you can query the database for each # not currently used and select
One possibility would be to make a DB table with 2 columns. One where
each row has a value from through , and the other
column marked as for used. When you need to generate the random number
you can query the database for each # not currently used and select
randomly from the v
Chris Snyder wrote:
Doing something like $random = $microtime . "_" . rand( 0, 256 );
gives you non-repeating pseudo-randomness.
md5(uniqid(rand(), true))
// as suggested in the manual
is harder to guess -- but now you're talkin' 32 chars.
(as usual it depends on what you're tryin' to do)
--
On Tue, Mar 10, 2009 at 11:54 AM, Dan Cech wrote:
> Chris Snyder wrote:
>> Add a random number to a sufficiently deep timestamp (microseconds)
>> and you will have a non-repeating random number. But you can't shorten
>> it to 8 characters or whatever -- you have to keep the full timestamp
>> in or
Dan Cech wrote:
...
If you're trying to generate relatively short pseudo-random IDs to
thwart guesses, then the simplest method is going to be the
previously-recommended approach of generating a random number and
checking if it has already been used, rinse and repeat until you find
one that has
Even the numbers game is not random. Some lotto numbers have come up 10X
then others. It's the ink on the ball. Shifts the weight.
But back to reality, you can get a pretty decent random number, for all
practical purposes using the tips covers in this discussion.
On Tue, Mar 10, 2009 at 11:54 AM
Chris Snyder wrote:
> Add a random number to a sufficiently deep timestamp (microseconds)
> and you will have a non-repeating random number. But you can't shorten
> it to 8 characters or whatever -- you have to keep the full timestamp
> in order to maintain non-repeatability.
Not really, if you ad
On Tue, Mar 10, 2009 at 11:15 AM, Edward Potter wrote:
>
> Go down to Prince & Broadway, stop the first model that walks by, then the
> next, etc. Ask them for a random number. Believe me you will NEVER get the
> same number twice. And they will never repeat! All laws of Physics go
> straight ou
Well, it's easy.
Go down to Prince & Broadway, stop the first model that walks by, then the
next, etc. Ask them for a random number. Believe me you will NEVER get the
same number twice. And they will never repeat! All laws of Physics go
straight out the window. Even Einstein gave in.
Just my 2
using tim's idea: get a uniqid, convert it to numbers and shift the
difference :)
- get a uniqid
- convert the chars to numbers using php.net/ord
- use the 8 first numbers
(would be an alternative to rand() for 8-digits)
On Tue, Mar 10, 2009 at 9:48 AM, Tim Gales wrote:
> chad qian wrote:
>
chad qian wrote:
Hi,
I need to generate random 8-digit numbers continuously.And no
duplication among all those numbers.In other word,every single 8-digit
number must be unique.How to do php programming?
Change your specification to 13 characters and use the function uniqid
Uniqid is driven by
the easiest:
$isInUse = 0 ;
while ($isInUse == 0) {
$yourNumber = rand(0,9) . rand(0,9) . rand(0,9) (8 times)
/* check here if $yourNumber is already in use and save the value in
$isInUse */
}
without saving the previous you will never be sure if you have duplicates
best,
fernando
On
On Mon, Mar 9, 2009 at 9:56 PM, chad qian wrote:
> Hi,
> I need to generate random 8-digit numbers continuously.And no
> duplication among all those numbers.In other word,every single 8-digit
> number must be unique.
>
It is not mathematically feasible to continuously generate unique random
num
chad qian wrote:
Hi,
I need to generate random 8-digit numbers continuously.And no
duplication among all those numbers.In other word,every single 8-digit
number must be unique.How to do php programming?
Thanks a lots!
chad
How random are you aiming for? As far as I know none of the progra
Hi,
I need to generate random 8-digit numbers continuously.And no duplication among
all those numbers.In other word,every single 8-digit number must be unique.How
to do php programming?
Thanks a lots!
chad
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