Вы можете использовать array_walk
и array_merge
$arr1 = Array (
'2019-04-29' => Array (
'0' => 366,
'1' => 82,
'2' => 44
) ,
'2019-04-30' => Array (
'0' => 330,
'1' => 115,
'2' => 55
)
);
$arr2 = Array ( '0' => 492 ,'1' => 500 ) ;
$index = 0;
$res=[];
array_walk($arr1, function($v,$k) use (&$res,$arr2,&$index){
$res[] = array_merge(array($arr2[$index]),$v);
$index++;
});
echo '<pre>';
print_r($res);
Результат
Array
(
[0] => Array
(
[0] => 492
[1] => 366
[2] => 82
[3] => 44
)
[1] => Array
(
[0] => 500
[1] => 330
[2] => 115
[3] => 55
)
)