regex to match only 5 letter words

Question

I have an array and want to retrieve only 5 letter words, nothing longer, I have tried to use

$new = preg_grep("/.{5}/", $array);

but that resulted in any word that is at least 5 letters long. I want any word that is at most 5 letters long.

Answer 1

You need to use the start (^) and end ($) modifiers, so

$new = preg_grep("/^.{5}$/", $array);

However, more efficient might be to just do a strlen based filter:

function len5($v){
   return strlen($v) == 5;
}
$new = array_filter($array, 'len5');

Answer 2

Use the regex below to match words from 1 to 5 characters. \b is a word boundary

/\b\w{1,5}\b/