$arr = [
    'one' => 12,
    'two' => 5,
    1 => 3,
];

//foreach
foreach ($arr as $key => $value) {
    var_dump("$key=>$value");
}

//each
while ($element = each($arr)) {
    var_dump(sprintf('%s=>%s', $element['key'], $element['value']));
}

//list each
while (list($key, $value) = each($arr)) {
    var_dump("$key=>$value");
}

//key current
$i = 0;
while ($i < count($arr)) {
    var_dump(sprintf('%s=>%s', key($arr), current($arr)));
    next($arr);
    $i++;
}

//array_keys
for ($j = 0; $j < count($keys = array_keys($arr)); $j++) {
    var_dump(sprintf('%s=>%s', $keys[$j], $arr[$keys[$j]]));
}