如何把这两个函数相同的键值相加形成新的数组

<?php
$a1 = &#39;10,20,30,40;1,2,3,4&#39;;//分号无限往后扩展
$a = explode(&#39;;&#39;, $a1);
$b1 = &#39;11111;22222&#39;;//分号无限往后扩展，能与$a1对齐叠加
$b = explode(&#39;;&#39;, $b1);

print_r($a);
print_r($b);
?>

Array ( [0] => 10,20,30,40 [1] => 1,2,3,4 ) Array ( [0] => 11111 [1] => 22222 )

Array ( [0] => 10,20,30,40,11111 [1] => 1,2,3,4,22222)

$a1 = '10,20,30,40;1,2,3,4';//分号无限往后扩展
$a = explode(';', $a1);
$b1 = '11111;22222';//分号无限往后扩展，能与$a1对齐叠加

$b = explode(';', $b1);
$c = array_map(null, $a, $b);
print_r($c);

Array
(
    [0] => Array
        (
            [0] => 10,20,30,40
            [1] => 11111
        )

    [1] => Array
        (
            [0] => 1,2,3,4
            [1] => 22222
        )

)

$a1 = '10,20,30,40;1,2,3,4';//分号无限往后扩展
$a = explode(';', $a1);
$b1 = '11111;22222';//分号无限往后扩展，能与$a1对齐叠加
$b = explode(';', $b1);
 
$c=array();
foreach($a as $key=>$value){
    $c[]=$value.",".$b[$key];
}
echo '

Array
(
    [0] => 10,20,30,40,11111
    [1] => 1,2,3,4,22222
)