dump() 把数组以数组格式数组，有益于调试
function dump($vars,$label = '',$return = false){
if (ini_get('html_errors')) {
$content = "

\n"; 
if ($label != '') { 
$content .= "
{$label} :
\n"; 
} 
$content .= htmlspecialchars(print_r($vars,true)); 
$content .= "\n

\n";
} else {
$content = $label . " :\n" . print_r($vars,true);
}
if ($return) { return $content; }
echo $content;
return null;
}
array_remove_empty()去除数组中为空的元素
function array_remove_empty(& $arr,$trim = true){
foreach ($arr as $key => $value) {
if (is_array($value)) {
array_remove_empty($arr[$key]);
} else {
$value = trim($value);
if ($value == '') {
unset($arr[$key]);
} elseif ($trim) {
$arr[$key] = $value;
}
}
}
}
array_chunk() PHP默认函数 作用是把函数平均分组