我正在制作一个图像板，无法弄清楚链接引用

Question

What I'm trying to do is fairly simple, but I can't figure it out. I'd like for a body of text to be scanned for anything that looks like >>1234 and be replaced with <a href="1234">>>1234</a> I can't conceive of a way to do this, although I can do parts. Writing a regex is easy enough for finding instances of >>1234 but it can't help me with the rest. This realistically can be done in two ways, the client being fed the text as-is and then using javascript to format it, or the server processing the text each time and spitting back out the formatted version.

Here's the github page: https://github.com/4tran/VIB

Here's an example of a regex I've tried that has worked somewhat:

<?php
function formatLink($post) {
    if(preg_match('/^\>\>([0-9]+)$/', $post)) {
      echo $post;
    }
}
formatLink(">>10"); // returns ">>10"
formatLink("spaghetti"); // returns ""
formatLink(">>10 spaghetti"); // returns ""
?>

Any help would be greatly appreciated, I'm really stuck here.

EDIT: I FIGURED OUT SOMETHING. Okay, so for anyone who'd like to help, I now have a very good reference for what I want to do. I figured out the second part of this before the first, the second part being text quoting. Here's the code:

$re = "/^^(>[a-zA-Z0-9_ ]*$)/mi";
$subst = "<p class=\"quote\">$1</p>";
foreach ($boards as $x) {
  $x = $db->real_escape_string($x);
  $db->real_query("SELECT * FROM posts_".$x." ORDER BY timestamp DESC LIMIT 1");
  $res = $db->use_result();
  while ($row = $res->fetch_assoc()) {
    $str = str_replace("\r\n", "\n", $row['content']);
    $str = str_replace("\r", "\n", $str);
    $content = preg_replace($re, $subst, $str);
    echo "<p style=\"font-size:110%;\">/$x/ - </p>" . "<p>" . nl2br($content) . "<a href=\"" . "$x/" . $row['op'] . "\"> [reply]</a></p><br/>";
  }
}

FINAL EDIT: I got the first part now as well.

https://regex101.com/r/kC1bM7/3

Answer 1

Don't have the closing anchor $ , the remaining text breaks that. The quantifier will find all additional numbers. (You also could take off the leading anchor ^ if the >>number is allowed anywhere in the string, in both examples it was leading so I think that is constant?).

Try:

^(>>\d+)

Demo: https://regex101.com/r/kC1bM7/2

You also should encode the > s as their entity if you are using that in HTML, > .

PHP Usage I'd use something like:

preg_replace('/^>>(\d+)/', '>>$1', $string);

Also not the greater than symbol has no special meaning in regex so it doesn't need to be escaped.