array_slice()
<?php
$a=array("red","green","blue","yellow","brown");
print_r(array_slice($a,2)); //Array ( [0] => blue [1] => yellow [2] => brown )
?> trim()
<?php
$str='1,2,3,4,';
trim($str,',');
?> array_filter($array)
去除数组中值为 ' ' 和 NULL 和 false 的项