PHP：根据ID列表从多维数组中高效筛选特定记录

<?php
// 目标ID列表
$targetIds = ["1", "2", "12", "43", "52"];

// 原始多维数据数组
$sourceData = [
    ["id" => "12", "name" => "Robert", "surname" => "Plant"],
    ["id" => "43", "name" => "Jimmy", "surname" => "Page"],
    ["id" => "8", "name" => "Mary", "surname" => "Stilton"],
    ["id" => "1", "name" => "John", "surname" => "Doe"]
];
?>

<?php
// 错误的尝试示例
$filteredRecords = [];
foreach ($targetIds as $id) {
    // 这里的 $sourceData['id'] 是错误的，因为 $sourceData 是一个由多个子数组组成的多维数组
    // 它没有直接的 'id' 键来形成一个ID列表
    if (in_array($id, $sourceData['id'])) { // 这会导致错误或无法达到预期
        // ...
    }
}
?>

<?php
$targetIds = ["1", "2", "12", "43", "52"];
$sourceData = [
    ["id" => "12", "name" => "Robert", "surname" => "Plant"],
    ["id" => "43", "name" => "Jimmy", "surname" => "Page"],
    ["id" => "8", "name" => "Mary", "surname" => "Stilton"],
    ["id" => "1", "name" => "John", "surname" => "Doe"]
];

$filteredRecords = []; // 用于存储匹配到的记录

// 遍历目标ID列表
foreach ($targetIds as $whitelistedId) {
    // 遍历原始多维数据数组中的每一条记录
    foreach ($sourceData as $record) {
        // 检查当前记录的 'id' 字段是否存在且与白名单ID匹配
        if (isset($record['id']) && $record['id'] == $whitelistedId) {
            $filteredRecords[] = $record; // 将匹配的整条记录添加到结果数组
            // 如果确定每个ID在 $sourceData 中是唯一的，
            // 找到匹配后可以立即跳出内层循环，提高效率。
            // break;
        }
    }
}

echo "<h3>解决方案一：嵌套循环匹配</h3>";
echo "<pre>";
print_r($filteredRecords);
echo "</pre>";
/*
预期输出:
Array
(
    [0] => Array
        (
            [id] => 12
            [name] => Robert
            [surname] => Plant
        )

    [1] => Array
        (
            [id] => 43
            [name] => Jimmy
            [surname] => Page
        )

    [2] => Array
        (
            [id] => 1
            [name] => John
            [surname] => Doe
        )

)
*/
?>

<?php
$targetIds = ["1", "2", "12", "43", "52"];
$sourceData = [
    ["id" => "12", "name" => "Robert", "surname" => "Plant"],
    ["id" => "43", "name" => "Jimmy", "surname" => "Page"],
    ["id" => "8", "name" => "Mary", "surname" => "Stilton"],
    ["id" => "1", "name" => "John", "surname" => "Doe"]
];

$indexedSourceData = [];
// 第一次遍历：将 $sourceData 转换为以 'id' 为键的关联数组
foreach ($sourceData as $record) {
    if (isset($record['id'])) {
        $indexedSourceData[$record['id']] = $record;
    }
}

$filteredRecords = [];
// 第二次遍历：根据目标ID从预处理的数组中直接查找
foreach ($targetIds as $id) {
    if (isset($indexedSourceData[$id])) {
        $filteredRecords[] = $indexedSourceData[$id];
    }
}

echo "<h3>解决方案二：预处理源数据为关联数组</h3>";
echo "<pre>";
print_r($filteredRecords);
echo "</pre>";
?>

<?php
$targetIds = ["1", "2", "12", "43", "52"];
$sourceData = [
    ["id" => "12", "name" => "Robert", "surname" => "Plant"],
    ["id" => "43", "name" => "Jimmy", "surname" => "Page"],
    ["id" => "8", "name" => "Mary", "surname" => "Stilton"],
    ["id" => "1", "name" => "John", "surname" => "Doe"]
];

// 将目标ID列表转换为一个以ID为键的关联数组，便于快速查找
$targetIdsMap = array_flip($targetIds);

// 使用 array_filter 结合匿名函数进行筛选
$filteredRecords = array_filter($sourceData, function($record) use ($targetIdsMap) {
    // 检查记录的 'id' 是否存在，并且该 'id' 是否在 $targetIdsMap 中
    return isset($record['id']) && isset($targetIdsMap[$record['id']]);
});

// array_filter 默认会保留原数组的键，如果需要重置为从0开始的索引，可以使用 array_values
$filteredRecords = array_values($filteredRecords);

echo "<h3>解决方案三：使用 array_filter 和 array_flip</h3>";
echo "<pre>";
print_r($filteredRecords);
echo "</pre>";
?>