PHP 多维数组操作：将键值对移动或添加到首位

<?php

function push_title_to_front(&$arr) {
    $new_svg = [];
    $title_found = false;

    foreach ($arr['svg'] as $svg) {
        if (array_key_exists('title', $svg)) {
            // 如果找到 title，更新 $new_svg 的第一个元素的 title 值
            $new_svg[0]['title'] = $svg['title'];
            $title_found = true;
        } else {
            // 如果没有找到 title，将当前元素添加到 $new_svg 中
            $new_svg[] = $svg;
        }
    }

    // 如果原始数组中没有 title，则在 $new_svg 的第一个位置添加一个默认的 title
    if (!$title_found) {
        array_unshift($new_svg, ['title' => 'test']);
    }

    // 将处理后的 $new_svg 赋值回原始数组的 'svg' 键
    $arr['svg'] = $new_svg;
}

// 示例用法
$arr = [
    "svg" => [
        ["@style" => "overflow:visible", "@xlink:href" => "test.png"],
        ["g" => "", "@id" => "Layer_2"],
        ["g" => "", "@id" => "Layer_3"],
        ["title" => "Fred"]
    ],
    "@version" => 1.2,
    "@baseProfile" => "tiny-ps",
    "@id" => "Layer_1",
    "@xmlns" => "http://www.w3.org/2000/svg"
];

push_title_to_front($arr);
print_r($arr);

// 示例用法2，如果原始数组中没有 title
$arr2 = [
    "svg" => [
        ["@style" => "overflow:visible", "@xlink:href" => "test.png"],
        ["g" => "", "@id" => "Layer_2"],
        ["g" => "", "@id" => "Layer_3"]
    ],
    "@version" => 1.2,
    "@baseProfile" => "tiny-ps",
    "@id" => "Layer_1",
    "@xmlns" => "http://www.w3.org/2000/svg"
];

push_title_to_front($arr2);
print_r($arr2);

?>