array array_filter ( array $array [, callable $callback [, int $flag = 0 ]] )

$arr2 = array('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5,'f'=>6);
  $resArr2=array_filter($arr2,'fun_odd');//其中的fun_odd必须加引号，不能加()
  print_r($resArr2);
  function fun_odd($arr){
  if($arr % 2 == 1){
    return $arr;
  }
  }

$entry = array( 
             0 => '蓝色夏威夷的博客', 
             1 => false, 
             2 => 1, 
             3 => null, 
             4 => '', 
             5 => 'https://www.jb51.net', 
             6 => '0',
             7 => array(),
             8 => 0
          );
$validarr = array_filter($entry);
print_r($validarr);
//输出结果：
Array
(
    [0] => 蓝色夏威夷的博客
    [2] => 1
    [5] => https://www.jb51.net
)