selecting words separated with comma with PHP

A string contains some words separate开发者_开发技巧d by comma or space. Using PHP, I want to select first three words which have have minimum 4 characters(a-Z, 0-9, -, _, #). For example

$words = aa, one, ab%c, four, five six#

How to select 'four', 'five', six# ? (probably with for each?)

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Dalen's suggestion would run much faster if you have no strict requirements for characters allowed. But here is a regex solution since you mention character requirements.

$words = 'aa, one, ab%c, four, five six#';
preg_match_all('/([a-z0-9_#-]{4,})/i', $words, $matches);
print_r($matches);

And you'll just have to cut out what you want from the array after like in Dalen's answer.

---

    //turn string to an array separating words with comma    
    $words = explode(',',$words);
    $selected = array();
    foreach($words AS $word)
    {
       //if the word has at least 4 chars put it into selected array
       if(strlen($word) > 3)
          array_push($selected,$word);
    }

    //get the first 3 words of the selected ones
    $selected = array_slice($selected, 0, 3);

this won't check for the characters, just for the length of the word. you'll need to edit the condition with a regexp