* 这里的使用场景是从数据表里查询出来的列表，每隔一定的数量加入一条广告数据 *

<?php

// 某信息数据列表
$list = [
    ['a1' => 'a1', 'b1' => 'b1'],
    ['a2' => 'a2', 'b2' => 'b2'],
    ['a3' => 'a3', 'b3' => 'b3'],
    ['a4' => 'a4', 'b4' => 'b4'],
    ['a5' => 'a5', 'b5' => 'b5'],
    ['a6' => 'a6', 'b6' => 'b6'],
    ['a7' => 'a7', 'b7' => 'b7'],
    ['a8' => 'a8', 'b8' => 'b8'],
    ['a9' => 'a9', 'b9' => 'b9'],
    ['a10' => 'a10', 'b10' => 'b10'],
];

// 广告列表，尽量多查询一点出来
$listAd = [
    ['AD1' => 'AD1', 'AD1' => 'AD1'],
    ['AD2' => 'AD2', 'AD2' => 'AD2'],
    ['AD3' => 'AD3', 'AD3' => 'AD3'],
    ['AD4' => 'AD4', 'AD4' => 'AD4'],
    ['AD5' => 'AD5', 'AD5' => 'AD5'],
    ['AD6' => 'AD6', 'AD6' => 'AD6'],
    ['AD7' => 'AD7', 'AD7' => 'AD7'],
    ['AD8' => 'AD8', 'AD8' => 'AD8'],
    ['AD9' => 'AD9', 'AD9' => 'AD9'],
];

$page = 3;
$limit = 10;
$listCount = ($page - 1) * $limit;
$insertCount = 12;

$j = floor($listCount / $insertCount);
$listNews = [];
foreach ($list as $value) {

    if ( $listCount != 0 && $listCount % $insertCount == 0 ) {

        if (isset($listAd[$j])) {
            $listNews[] = $listAd[$j];
        }
        $j++;
    }

    $listNews[] = $value;
    $listCount++;
}

echo "<pre>";
var_dump($listNews);