PHP正则表达式实现按WordPress<!--nextpage-->分割内容

Hey there! Let's work through this regex problem for your PHP 7.1 setup. Here are straightforward solutions for both of the array formats you're targeting:

This format groups each page's content with its following <!--nextpage--> tag (the last entry only has the page content). Instead of a complex regex match, splitting the string first and then modifying the parts is often more readable:

$the_content = " <h2>1page</h2><p>...</p> <!--nextpage--> <h2>2page</h2><p>...</p> <!--nextpage--> <h2>3page</h2><p>...</p> <!--nextpage--> <h2>4page</h2><p>...</p> <!--nextpage--> <h2>5page</h2><p>...</p> ";

// Split the content at each nextpage separator
$pageParts = preg_split('/\s*<!--nextpage-->\s*/', trim($the_content));

// Build the desired array
$matches1 = [];
foreach ($pageParts as $index => $part) {
    if ($index < count($pageParts) - 1) {
        // Add the separator back to all except the last part
        $matches1[] = $part . '&lt;!--nextpage--&gt;';
    } else {
        $matches1[] = $part;
    }
}

print_r($matches1);

If you prefer a regex match approach instead, you can use this preg_match_all pattern to capture each block directly:

preg_match_all('/(?s)(<h2>.*?<\/p>\s*<!--nextpage-->)|(<h2>.*?<\/p>)\s*$/', $the_content, $matches);
$matches1 = array_merge(array_filter($matches[1]), array_filter($matches[2]));
print_r($matches1);

For this format, we'll use preg_split with the PREG_SPLIT_DELIM_CAPTURE flag—this lets us capture the separators alongside the page content, resulting in the alternating array you want:

$the_content = " <h2>1page</h2><p>...</p> <!--nextpage--> <h2>2page</h2><p>...</p> <!--nextpage--> <h2>3page</h2><p>...</p> <!--nextpage--> <h2>4page</h2><p>...</p> <!--nextpage--> <h2>5page</h2><p>...</p> ";

// Split and capture both content and separators
$matches2 = preg_split(
    '/(\s*<!--nextpage-->\s*)/', 
    trim($the_content), 
    -1, 
    PREG_SPLIT_DELIM_CAPTURE
);

// Clean up empty elements and reindex the array
$matches2 = array_values(array_filter($matches2, function($item) {
    return trim($item) !== '';
}));

print_r($matches2);

The PREG_SPLIT_DELIM_CAPTURE flag tells PHP to include the matched separators (the part in parentheses) in the output array, which gives us that alternating content-separator structure.

内容的提问来源于stack exchange，提问作者kbash