php自定义过滤字符函数

php自定义过滤字符函数：

 

	/**
	 * 保留指定类型的字符
	 * @param $content => 
	 * @param $type    => 1整数，2小数，3字母，4汉字，5小数+字母+下划线，6数字+字母+汉字
	 * @return string
	**/
function glstr($content,$type=1){
		if(strlen($content)<1) return $content;
		switch($type){
			case 1:
				$content = preg_replace("/[^0-9]/u","",$content);
				break;
			case 2:
				$content = preg_replace("/[^0-9\.]/u","",$content);
				break;
			case 3:
				$content = preg_replace("/[^a-zA-Z_]/u","",$content);
				break;
			case 4:
				$content = preg_replace("/[^_\x{4e00}-\x{9fa5}]/u","",$content);
				break;
			case 5:
				$content = preg_replace("/[^0-9\.a-zA-Z_]/u","",$content);
				break;
			case 6:
				$content = preg_replace("/[^0-9\.a-zA-Z_\x{4e00}-\x{9fa5}]/u","",$content);
				break;
			case 7:
				$content = preg_replace("/[^0-9\.a-zA-Z_\x{4e00}-\x{9fa5}\@\#\%\+\-\.\,\/]/u","",$content);
				break;
		}
		return $content;
	}