Question

How to find the indexes of the first and last occurrences of an element in array in PHP

Answer 1

function findFirstAndLastIndex($array, $element) {
    $first = -1;
    $last = -1;
    $size = count($array);
    
    for ($i = 0; $i < $size; $i++) {
        if ($array[$i] != $element) {
            continue;
        }
        
        if ($first == -1) {
            $first = $i;
        }
        
        $last = $i;
    }
    
    if ($first != -1) {
        echo "First Occurrence = " . $first . "\n";
        echo "Last Occurrence = " . $last . "\n";
    }
    else {
        echo "Not Found";
    }
}

$array = array(3, 2, 4, 7, 3, 0, 9, 8, 7, 7, 12, 18);

$element = 7;

findFirstAndLastIndex($array, $element);




/*
run:

First Occurrence = 3
Last Occurrence = 9

*/

 

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