- array_reverse: documentation ( source)
- implode: documentation ( source)
- explode: documentation ( source)
- str_split: documentation ( source)
<?php
function longest_palendrome($string)
{
$words = explode(' ', $string);
$longest = '';
foreach ($words as $word) {
$letters = $reversed = str_split($word);
array_reverse($reversed);
if ($letters === implode('', $reversed) && strlen($word) > strlen($longest)) {
$longest = $word;
}
}
return $word;
}
echo longest_palendrome("i ama racecar");