$xml = simplexml_load_file($xmlfile);
$k = 0;
foreach ($xml->match as $item){
	$matchTime = $item->attributes()['matchTime'];//<match matchTime="" ...></match>节点属性
	if(DateDiff('h',$matchTime,$curTime) >= 3) {//数据筛选条件
		$delArr[] = $k;
	}
	$k++;
}
if(!empty($delArr)){//循环删除 因删除后match主键的变动 依次删除
	foreach ($delArr as $d=>$v) {
		unset($xml->match[$v-$d]);
	}
}
$xml->asXML($xmlfile);