PHP中实现多关键词首个匹配替换的高效策略

$keywords = ['game', 'gamers', 'gaming'];
$content = 'I am a gamer and I love playing video games. Video games are awesome. I have being a gamer for a long time. I love to hang-out with other gamer buddies of mine.';
$url = '/search?q=';

foreach ($keywords as $keyword) {
    $pattern = '/\b' . preg_quote($keyword, '/') . '\b/'; // 使用 preg_quote 防止特殊字符影响正则
    // 限制替换次数为1
    $content = preg_replace($pattern, "<a style=\"font-weight: bold;color:rgb(20, 23, 26);\" href=\"".$url.urlencode($keyword)."\">".$keyword."</a>", $content, 1);
}

echo $content;

$keywords = ['gamer', 'games'];
$content = 'I am a gamer and I love playing video games. Video games are awesome. I have being a gamer for a long time. I love to hang-out with other gamer buddies of mine.';
$url = '/search?q=';

// 组合所有关键词，使用 preg_quote 确保安全
$pattern = '/\b(' . implode('|', array_map('preg_quote', $keywords, array_fill(0, count($keywords), '/'))) . ')\b/';

// $0 会捕获整个匹配到的字符串
$content = preg_replace($pattern, "<a style=\"font-weight: bold;color:rgb(20, 23, 26);\" href=\"".$url.urlencode('$0')."\">$0</a>", $content);

echo $content;

<?php

/**
 * 针对文本内容中的多个关键词，只替换每个关键词的第一个匹配项。
 *
 * @param string $content 待处理的原始文本。
 * @param array $keywords 包含所有需要匹配和替换的关键词的数组。
 * @param string $replacementTemplate 替换内容的模板，其中 $0 或 $keyword 会被实际匹配的关键词替代。
 *                                    例如：'<a href="/search?q=$0">$0</a>'
 * @return string 处理后的文本。
 */
function replaceFirstMatchOfEachKeyword(string $content, array $keywords, string $replacementTemplate): string
{
    if (empty($keywords)) {
        return $content;
    }

    // 1. 构建正则表达式
    // 使用 preg_quote 确保关键词中的特殊字符被正确转义
    // 使用命名捕获组 (?<keyword>...) 来方便地在回调函数中获取匹配到的关键词
    $escapedKeywords = array_map(function($k) {
        return preg_quote($k, '/');
    }, $keywords);
    $pattern = '/\b(?<keyword>' . implode('|', $escapedKeywords) . ')\b/i'; // 'i' 标志表示不区分大小写匹配

    // 用于追踪已替换的关键词，必须通过引用传递给回调函数
    $usedKeywords = [];

    // 2. 使用 preg_replace_callback 执行替换
    $processedContent = preg_replace_callback(
        $pattern,
        function (array $matches) use (&$usedKeywords, $replacementTemplate) {
            $currentKeyword = $matches['keyword']; // 获取命名捕获组 'keyword' 的值

            // 3. 在回调函数中实现条件逻辑
            // 检查当前关键词是否已在 usedKeywords 数组中
            if (in_array(strtolower($currentKeyword), array_map('strtolower', $usedKeywords), true)) {
                // 如果已替换过，则返回原始匹配项，不做任何修改
                return $matches[0]; // $matches[0] 包含整个匹配到的字符串
            }

            // 如果是首次匹配，则将关键词添加到 usedKeywords 数组中
            $usedKeywords[] = $currentKeyword;

            // 执行替换操作
            // 替换模板中的 $0 或 $keyword 为实际匹配到的关键词
            $replacedString = str_replace(
                ['$0', '$keyword'],
                [$matches[0], $currentKeyword],
                $replacementTemplate
            );
            return $replacedString;
        },
        $content
    );

    return $processedContent;
}

// 示例用法
$string = 'I am a gamer and I love playing video games. Video games are awesome. I have being a gamer for a long time. I love to hang-out with other gamer buddies of mine.';
$keyWordsToMatch = ['gamer', 'games'];
$baseUrl = '/category/'; // 假设链接的基础URL

// 构造替换模板，将关键词转换为链接
// 注意：urlencode 用于确保关键词在URL中是合法的
$replacementLinkTemplate = '<a style="font-weight: bold;color:rgb(20, 23, 26);" href="' . $baseUrl . urlencode('$keyword') . '">$keyword</a>';

$finalString = replaceFirstMatchOfEachKeyword($string, $keyWordsToMatch, $replacementLinkTemplate);

echo "原始字符串:\n" . $string . "\n\n";
echo "处理后字符串:\n" . $finalString . "\n\n";

// 另一个简化示例，仅用于演示替换逻辑
$string2 = 'gamer thing gamer games test games';
$keyWordsToMatch2 = ['gamer', 'games'];
$replacementSimpleTemplate = '~${keyword}~'; // 使用 ${keyword} 或 $keyword

$finalString2 = replaceFirstMatchOfEachKeyword($string2, $keyWordsToMatch2, $replacementSimpleTemplate);
echo "简化示例结果:\n" . $finalString2 . "\n";

原始字符串:
I am a gamer and I love playing video games. Video games are awesome. I have being a gamer for a long time. I love to hang-out with other gamer buddies of mine.

处理后字符串:
I am a <a style="font-weight: bold;color:rgb(20, 23, 26);" href="/category/gamer">gamer</a> and I love playing video <a style="font-weight: bold;color:rgb(20, 23, 26);" href="/category/games">games</a>. Video games are awesome. I have being a gamer for a long time. I love to hang-out with other gamer buddies of mine.

简化示例结果:
~gamer~ thing gamer ~games~ test games