PHP代码执行权重优先级

生成所有数组再根据随机数根据key定位到id

$arr = [
    1=>12,
    2=>123,
    3=>12,
    4=>111,
];

$supplier = [];
foreach ($arr as  $key=>$item) {
    $supplier = array_merge($supplier,array_fill(0,$item,$key));
}

echo $supplier[rand(0,count($supplier)-1)];exit;