- var_dump: documentation ( source)
- array_reduce: documentation ( source)
- explode: documentation ( source)
<?php
$string = "2014-10-10,2689,100.20,99.33,2613 2014-10-13,2628,101.10,99.98,2741 2014-10-14,2741,100.06,99.20,2658 2014-10-15,2741,100.06,99.20,2658";
$date = array_reduce(explode(' ', $string), function($carry, $item) { $carry[] = explode(',', $item)[0]; return $carry; });
var_dump($date);