binary_search.php

<?php
/* Binary Search implementation in PHP */
function binarySearch(Array $arr, $item) {
    $low = 0;
    $high = count($arr) - 1;
	$found = false;

	while ($low <= $high) {
		$mid = $low + ($high - $low) / 2; //Midpoint of the Search Space

		if ($arr[$mid] === $item) { //Found the element
			$found = true;
			break;
		} else {
			if ($item < $arr[$mid]) { //Need to search in the left half of the search space
				$high = $mid - 1;
			} else { //Need to search in the right half of the search space
				$low = $mid + 1;
			}
		}
	}

	return $found;
}


/************ Testing Binary Search Implementation ***************/

// This list must be sorted. If it is not given as sorted, sort it first, then call the binarySearch method
$testList = array(0, 1, 2, 8, 13, 17, 19, 32, 42);
echo binarySearch($testList, 3) ? 'True' : 'False';
echo PHP_EOL;
echo binarySearch($testList, 13) ? 'True' : 'False';

?>