Quick example code to take an array of times and randomly grab ten elements from that array. If the source array has less than ten elements, grab all of the elements in a random order.

gistfile1.php

<?php
	// set up array with slides
	$slides = array(1, 2, 3, 4, 5);
	//$slides = array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
	//$slides = array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);


	// get ten random array elements to display
	$length = count($slides);
	
	$maxLength = 10;
	if ($length < 10) {
		$maxLength = $length;
	}
	echo "Array length: $length and Max length: $maxLength\n";
	$length--;
	
	$randSlides = array(); // create empty array that hold the elements
	                       // to disply
	for ($i = 0; $i < $maxLength; $i++) {
		$n = rand(0, $length);
				
		if (empty($n)) {
			$n = 0;
		}
				
		if (! in_array($n, $randSlides)) {
			array_push($randSlides, $n);
		} else {
			--$i; // decrement $i causing the loop to rerun this
			      // illiteration
            		continue;
    		}
	}
	
	echo 'Number of elements in $randSlides: ' . count($randSlides) . "\n";
	
	// Display the randomly selected slides
	foreach($randSlides as $slide) {
    		echo $slides[$slide] . ' ';
	}
?>