4 ways to get file extensions in PHP_php tips

The examples in this article describe 4 ways to obtain file extensions in PHP. Share it with everyone for your reference, the details are as follows:

$filename="123.jpg";
//方法一：
function get_ext($file_name){
  return array_pop(explode('.', $file_name));
  //用.号对字符串进行分组
}
echo get_ext($filename);
//方法二：
$fileEx=strtolower(substr(strrchr($filename,"."),1));
echo $fileEx;
//方法三：
$extend=pathinfo($filename);
echo $extend['extension'];
//方法四：
$filetype=array("image/gif","image/jpeg");
//判断文件扩展名类型是否在该 数组中
if(in_array($_FILES['file']['type'],$filetype)){
//针对上传文件判断
  echo $_FILES['file']['type'];
}

I hope this article will be helpful to everyone in PHP programming.