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Re: Random function [message #180556 is a reply to message #180551]

Tue, 26 February 2013 10:18

M. Strobel
Messages: 386
Registered: December 2011

Karma:

Senior Member

Am 25.02.2013 23:42, schrieb Salvatore:
> On 2013-02-25, sonnichjensen(at)gmail(dot)com <sonnichjensen(at)gmail(dot)com> wrote:
>> I use the rand function to get 10 items of 1808 current itemes.
>
> If you want ten random items from an array, you could try the following:
>
> <?php
> // This is the big array you're pulling something out of.
> $lotsOfItems = array( /* ... */ );
>
> // This is the empty array that will eventually contain the ten random
> // items.
> $tenRandomItems = array();
>
> // Generate a range of numbers between 0 and the number of items minus
> // one.
> $range = range(0, count($lotsOfItems) - 1);
>
> // Shuffle the array of numbers.
> shuffle($range);
>
> while (count($tenRandomItems) < 10) {
> $randomOffset = array_shift($range);
> $tenRandomItems []= $lotsOfItems[$randomOffset];
> }
> ?>
>
> Using this code, you will never, ever have a duplicate item. However, it
> will be far more computationally expensive than using rand() or
> mt_rand().
>

Random number generation on computers is a research subject for at least 30 years.

You would never get anywhere near the current state of art with a self written solution.

/Str.

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[Message index]

		Random function By: Sonnich Jensen on Mon, 25 February 2013 20:48
		Re: Random function By: Salvatore on Mon, 25 February 2013 20:57
		Re: Random function By: Luuk on Mon, 25 February 2013 21:13
		Re: Random function By: Jerry Stuckle on Mon, 25 February 2013 21:42
		Re: Random function By: The Natural Philosoph on Mon, 25 February 2013 22:12
		Re: Random function By: Robert Heller on Tue, 26 February 2013 01:46
		Re: Random function By: Jerry Stuckle on Mon, 25 February 2013 21:39
		Re: Random function By: The Natural Philosoph on Mon, 25 February 2013 22:11
		Re: Random function By: Salvatore on Mon, 25 February 2013 22:42
		Re: Random function By: M. Strobel on Tue, 26 February 2013 10:18
		Re: Random function By: Paul Herber on Tue, 26 February 2013 13:52
		Re: Random function By: Markus Grob on Wed, 27 February 2013 11:17
		Re: Random function By: Thomas 'PointedEars' on Wed, 27 February 2013 23:22

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