i want to a generate random number between 1 to 20 giving priority to some number.
Such as I want 6 for 50% time
11 for 20% time
(it mean that if i generate 10 times then I will get 6 at least five times, and 11 and least 2 times)



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Md. Zakir Hossain (Raju)
www.rubd.net
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Best Regard:
Md. Zakir Hossain (Raju)

www.rajuru.xenexbd.com - my blog with PHP scripts, PHP Book Review and many more

is there anyone to help me, moderator please help me


Best Regard:
Md. Zakir Hossain (Raju)
www.rubd.net
www.xenex.rubd.net
www.forum.rubd.net

If you want it to do that, then its not very random, is it? :/

Only way to do that kind of thing is with some complex math.

P.S. why you want a moderator to help? Theres plenty of other good coders that aren't mods ;)

Many shoes,

Jamez/SiliconFuRy

thanks for reply,

but can you help me giving the algorithm

none yet help me that's why i wanted moderator help

Best Regard:
Md. Zakir Hossain (Raju)
www.rubd.net
www.xenex.rubd.net
www.forum.rubd.net

Well you're gonna have to devise a new function to do this. You're also gonna think how you're going to want to syntax the function, for instance...

MakeRandom(x,y,z);

where random is selected between x and y, and a 50% bias towards z, so
1,20,6 would pick a rnadom number between 1 and 20 with a 50% bias towards 6.

From this, you could generate an array, and populate it with the values from 1 and 20 (use a loop), but when you populate, make 50% of the values the value z (in our example, 6), so you'd get an array something like....

shoes = Array(1,2,3,4,5,6,7,8,9,10,6,6,6,6,6,6,6,6,6,6);

Then use array_rand(shoes) to pick a value from that.

Bingo :D

Many shoes,

Jamez/SiliconFuRy

Actually that prob wouldn't work so well, as the numbers from 11-20 would never be picked, but you can see what im basically getting at.

Many shoes,

Jamez/SiliconFuRy

Actually if you generate your array EACH type (dynamically) you call the function You COULD use that function. You create your array by populating your Biased numbers (i.e. the 50% as 6 and 20% as 11) then you fill the remaining values with a random number from using the srand and rand functions using a range from 1 to 20. Then you AGAIN use the SRAND and RAND function to determine which value from the array you are going to use.

In this way, (Statistically speaking) you will get the BIASED value as you suggest but still have a probablitiy of getting all the other numbers a smaller percentage of the time.

The key is to REPOPULATE the array EACH TIME, as SiliconFury points out, if you don't then you will definitely miss some values.

Hope this helps.


Paul Gardner
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Sounds good, I'd use the srand and rand function to populate the array with 50% of random values and the other 50% of the preferred bias value.

Many shoes,

Jamez/SiliconFuRy