New line to paragraph function

Question

I have this interesting function that I'm using to create new lines into paragraphs. I'm using it instead of the nl2br() function, as it outputs better formatted text.

function nl2p($string, $line_breaks = true, $xml = true) {  $string = str_replace(array('<p>', '</p>', '<br>', '<br />'), '', $string);  // It is conceivable that people might still want single line-breaks // without breaking into a new paragraph. if ($line_breaks == true)     return '<p>'.preg_replace(array("/([\n]{2,})/i", "/([^>])\n([^<])/i"), array("</p>\n<p>", '<br'.($xml == true ? ' /' : '').'>'), trim($string)).'</p>'; else      return '<p>'.preg_replace(     array("/([\n]{2,})/i", "/([\r\n]{3,})/i","/([^>])\n([^<])/i"),     array("</p>\n<p>", "</p>\n<p>", '<br'.($xml == true ? ' /' : '').'>'),      trim($string)).'</p>';  

}

The problem is that whenever I try to create a single line break, it inadvertently removes the first character of the paragraph below it. I'm not familiar enough with regex to understand what is causing the problem.

Answer 1

Here is another approach that doesn't use regular expressions. Note, this function will remove any single line-breaks.

function nl2p($string) {     $paragraphs = '';      foreach (explode("\n", $string) as $line) {         if (trim($line)) {             $paragraphs .= '<p>' . $line . '</p>';         }     }      return $paragraphs; } 

If you only need to do this once in your app and don't want to create a function, it can easily be done inline:

<?php foreach (explode("\n", $string) as $line): ?>     <?php if (trim($line)): ?>         <p><?=$line?></p>     <?php endif ?> <?php endforeach ?> 

Answer 2

The problem is with your match for single line breaks. It matches the last character before the line break and the first after. Then you replace the match with <br>, so you lose those characters as well. You need to keep them in the replacement.

Try this:

function nl2p($string, $line_breaks = true, $xml = true) {  $string = str_replace(array('<p>', '</p>', '<br>', '<br />'), '', $string);  // It is conceivable that people might still want single line-breaks // without breaking into a new paragraph. if ($line_breaks == true)     return '<p>'.preg_replace(array("/([\n]{2,})/i", "/([^>])\n([^<])/i"), array("</p>\n<p>", '$1<br'.($xml == true ? ' /' : '').'>$2'), trim($string)).'</p>'; else      return '<p>'.preg_replace(     array("/([\n]{2,})/i", "/([\r\n]{3,})/i","/([^>])\n([^<])/i"),     array("</p>\n<p>", "</p>\n<p>", '$1<br'.($xml == true ? ' /' : '').'>$2'),      trim($string)).'</p>';  }