Generating Random Numbers...

[famousb]

ok, i've done this before but can't remember how.<br>
I need to generate 100 unique random numbers ranging from 1-X, with X being a value enterred by the user.<br>
I thought i did this before through a query, but i can't seem to get it to work now. the formula i'm using now is<br>
<br>
Int([Upperbound]*Rnd())<br>
<br>
the problem with this is that it returns the same number 100 times, as oppossed to a different one. i know it's possible, i've done it before.<br>
<br>
thanks <p>Brian Famous<br><a href=mailto:bfamous@ncdoi.net>bfamous@ncdoi.net</a><br><a href= > </a><br>

 

[DougP]

Well if you want 100 differnt numbers with NO one EVER being the same then you have to keep track of them some how.<br>
Right. In an array or something...<br>
<br>
I guess 1-X means a number from 1 to X and not 1 Minus X<br>
<br>
<p> DougP<br><a href=mailto: dposton@universal1.com> dposton@universal1.com</a><br><a href= > </a><br>

 

[famousb]

yes, 1 to X, not 1 minus X. - sorry, too much green beer this weekend.<br>
<br>
and the recordsets will be around 5 million numbers, so i'm not too concerned about the possibility of generating the same number twice. i can always fix that on the back end.<br>
<br>
<p>Brian Famous<br><a href=mailto:bfamous@ncdoi.net>bfamous@ncdoi.net</a><br><a href= > </a><br>

 

[DougP]

Well I have noticed the same problem.<br>
Random is not very random<br>
What you have to do is keep track of each number it generates and force it to re-generate a new number until it comes up with a differnent one.<br>
This may take a while.<br>
<br>
<p> DougP<br><a href=mailto: dposton@universal1.com> dposton@universal1.com</a><br><a href= > </a><br>

 

[famousb]

well, this is the formula i came up with<br>
<br>
Random: Int(([UpperLimit])*Rnd([UpperLimit]-[PlaceHolder]))<br>
<br>
i put this in the Field line of the query, and then have a field named [PlaceHolder] that is linked to a table with the numbers 1 through 100 (100 being the largest sample i will need.)<br>
<br>
it prompts for the [UpperLimit] which is the number of records that i need to sample at the particular time. it seems to work pretty good so far so it will do, but it's not what i did before. i'm just not really going to worry about the possibility of generating the same number twice, i'll cross that bridge when i come to it. <p>Brian Famous<br><a href=mailto:bfamous@ncdoi.net>bfamous@ncdoi.net</a><br><a href= > </a><br>

 

[elizabeth]

If you used your numbers as the primary key in a new table, dupes would be thrown out for you.

 

[MikeAngelastro]

Use the Randomize statement. See below.<br>
<br>
Randomize Statement<br>
<br>
Initializes the random-number generator.<br>
<br>
Syntax:<br>
<br>
Randomize [number]<br>
<br>
The optional numberargument is aVariant or any validnumeric expression.<br>
<br>
Remarks:<br>
<br>
Randomize uses number to initialize the Rnd function's random-number generator, giving it a newseed value. If you omit number, the value returned by the system timer is used as the new seed value.<br>
<br>
If Randomize is not used, the Rnd function (with no arguments) uses the same number as a seed the first time it is called, and thereafter uses the last generated number as a seed value.<br>
<br>
Note: To repeat sequences of random numbers, call Rnd with a negative argument immediately before using Randomize with a numeric argument. Using Randomize with the same value for number does not repeat the previous sequence.<br>
<br>
<br>
Randomize Statement Example:<br>
<br>
This example uses the Randomize statement to initialize the random-number generator. Because the number argument has been omitted, Randomize uses the return value from the Timer function as the new seed value.<br>
<br>
Dim MyValue<br>
Randomize ' Initialize random-number generator.<br>
<br>
MyValue = Int((6 * Rnd) + 1) ' Generate random value between 1 and 6.<br>
<br>
Mike<br>