PHP正则表达式替换文本中的关键字，而不是锚标记内的关键字

I am trying to implement automatic hyperlink function for keywords.

The issue I am having that a keyword can be a part of other keyword. For example: potato, sweet potato. The function has to know not to hyperlink potato in sweet potato..

I am using regex and it actually works on different environments but not in my localhost and not in live version..

Working example:

$keywords_external = array(
  "Sweet potato" => "food/sweet-potato", 
  "Potato salads" => "food/potato-salads",
  "Potato" => "food/potato", 
);

$data = array(
  'post_content' => 'Sweet potato some text then potato then more text and then potato salads'
);

foreach($keywords_external as $key => $href) 
{
  $regex = '/<a\b(?=\s)(?:[^>=]|=\'[^\']*\'|="[^"]*"|=[^\'"\s]*)*"\s?>.*?<\/a>|('.$key.')/ims';

  $data['post_content'] = preg_replace_callback(
    $regex,
    function ($matches) {
        if (array_key_exists (1, $matches)) {
           return '<a href="https://example.com/">'. $matches[1] .'</a>';
        }
        return $matches[0];
    },
    $data['post_content']
  );
}

echo $data['post_content'];

Works on http://phpfiddle.org

Same example does not work in live version..

Any ideas to achieve same thing differently or why it does not might work in live version?

Thanks.

PHP VERSIONS
Localhost: PHP Version 7.0.12,
Live: PHP Version 7.0.15-1+deb.sury.org~xenial+1,
Live which works: PHP Version 5.4.45

[edit]: since you are dealing with multibyte characters, the code needs to be edited a little:

I don't know what is your exact problem but, this is the way I will do it (in a single pass):

// all keys must be lowercase
$keywords_external_path = array(
    "business analyst là gì" => "business-analyst/", 
    "tài liệu cho business analyst" => "tai-lieu-cho-business-analyst/", 
    "product manager là gì" => "product-manager-la-gi/", 
    "công việc của product manager" => "product-manager-phai-biet-dat-cau-hoi/", 
    "QA là gì" => "qc-la-gi-qa-la-gi/", 
    "QC là gì" => "qc-la-gi-qa-la-gi/", 
    "Kiểm thử phần mềm là gì" => "kiem-thu-phan-mem-ai-lam-chang-duoc/", 
    "Automation QA là gì" => "3-loi-khuyen-giup-ban-nang-cap-su-nghiep-qa/", 
    "Tester là gì" => "tester-thanh-cong/", 
    "kỹ năng của Tester giỏi" => "tester-thanh-cong/", 
    "công việc QA" => "qa-gioi/", 
    "Technical Architect là gì" => "how-to-become-ta/", 
);

//change the keys to lowercase (support multibyte characters)
mb_internal_encoding("UTF-8");
$keywords_external_path = array_combine(
    array_map('mb_strtolower', array_keys($keywords_external_path)), 
    $keywords_external_path
);

$data = array(
  'post_content' => '"business analyst là gì" => "business-analyst/", 
            "tài liệu cho business analyst" => "tai-lieu-cho-business-analyst/", 
            "product manager là gì" => "product-manager-la-gi/", 
            "công việc của product manager" => "product-manager-phai-biet-dat-cau-hoi/", 
            "QA là gì" => "qc-la-gi-qa-la-gi/", 
            "QC là gì" => "qc-la-gi-qa-la-gi/", 
            "Kiểm thử phần mềm là gì" => "kiem-thu-phan-mem-ai-lam-chang-duoc/", 
            "Automation QA là gì" => "3-loi-khuyen-giup-ban-nang-cap-su-nghiep-qa/", 
            "Tester là gì" => "tester-thanh-cong/", 
            "kỹ năng của Tester giỏi" => "tester-thanh-cong/", 
            "công việc QA" => "qa-gioi/", 
            "Technical Architect là gì" => "how-to-become-ta/"'
);

$base = 'http://yourdomain.com/'; // only if this is useful

$keywords_external = array_map(function ($i) {
    return preg_quote($i, '~');
}, array_keys($keywords_external_path));
rsort($keywords_external);

// to quickly discard useless positions (if you have many keywords):
// you can also do the same with the second letter
$keywords_first_letter = implode('',
    array_unique(
        array_reduce($keywords_external, function ($c, $i) {
            $c[] = mb_substr($i, 0, 1); return $c;
        }, [])
    )
);

$pattern = '~'
         . '(?=['. preg_quote($keywords_first_letter, '~') . '])'
         . '(?=\b\w|(?<!\S)\W)'
         . '(?:' . implode('|', $keywords_external) . ')'
         . '(?<=\w\b|\W(?!\S))~iu';

$result = preg_replace_callback($pattern, function ($m) use ($keywords_external_path, $base) {
    return '<a href="' . $base . $keywords_external_path[mb_strtolower($m[0])] . '">'
         . $m[0] . '</a>'; 
}, $data['post_content']);

echo $result;

demo with several php versions