PHP实现基于文本的简易搜索引擎功能

$documents = [
    ['id' => 1, 'title' => 'PHP搜索引擎', 'content' => '创建一个简易的PHP搜索引擎。'],
    ['id' => 2, 'title' => 'PHP数组教程', 'content' => '学习PHP中数组的使用方法。'],
    // 更多文档...
];

function extractKeywords($query) {
    $query = strtolower($query);
    $keywords = preg_split('/\s+/', $query); // 基于空格分割查询为关键字
    return array_unique($keywords); // 移除重复关键字
}

function searchDocuments($keywords, $documents) {
    $matches = [];
    foreach ($documents as $document) {
        $docText = strtolower($document['title'] . ' ' . $document['content']);
        $match = true;
        foreach ($keywords as $keyword) {
            if (strpos($docText, $keyword) === false) {
                $match = false;
                break;
            }
        }
        if ($match) {
            $matches[] = $document;
        }
    }
    return $matches;
}

function sortDocumentsByRelevance($keywords, $documents) {
    usort($documents, function ($a, $b) use ($keywords) {
        $aCount = $bCount = 0;
        $aText = strtolower($a['title'] . ' ' . $a['content']);
        $bText = strtolower($b['title'] . ' ' . $b['content']);
        foreach ($keywords as $keyword) {
            $aCount += substr_count($aText, $keyword);
            $bCount += substr_count($bText, $keyword);
        }
        return $bCount <=> $aCount;
    });
    return $documents;
}

$query = "PHP搜索";
$keywords = extractKeywords($query);
$matchedDocuments = searchDocuments($keywords, $documents);
$sortedDocuments = sortDocumentsByRelevance($keywords, $matchedDocuments);

// 显示结果
foreach ($sortedDocuments as $document) {
    echo "标题: " . $document['title'] . "<br>";
    echo "内容: " . $document['content'] . "<br><br>";
}