PHP function that produces acronym

I wrote this function because I couldn't find one that produces an acronym from a string of words.

Here's the script:

function acronym($longname) {

$letters=array();

$words=explode(' ', $longname);

foreach($words as $word) {

$word = (substr($word, 0, 1));

array_push($letters, $word);

}

$shortname = strtolower(implode($letters));

return $shortname;

}

// call the script like this:

$_POST['title'] = acronym($_POST['title']);

Semantic nl2br()

Here's a little PHP function that I wrote to replace nl2br() when it's actually a paragraph break that's required. It creates more semanic code for textarea fields being displayed from a mysql database. It replaces one \n with <br />but if there are 2 together, they are replaced with </p><p>. You initiate the first paragraph and end the last paragraph when you call the function.

Here's the function:
// define function
function lineBreaks($lines) {
// insert break tags
$lines = nl2br($lines);
// create an array of all the possible multiple break tags
$breaks = array("<br /><br />", "<br />\r\n<br />", "<br />\n<br />", "<br />\r<br />");
$paragraphs = "</p><p>";
// replace multiple break tags with paragraph tags
$lines = str_replace($breaks, $paragraphs, $lines);
return $lines;
}

Here's how you call it:
// $row['details'] is the name of the field. It could be anything.
echo "<p>".lineBreaks($row['details'])."</p>\n";