What are the several ways to get extensions in php

function getExt1{ return end(explode(".",$file);) }

function getExt2{ return substr($file,strrpos($file,'.')+1); }

function getExt3($file){ return array_pop(explode(‘.’,$file)); }

function getExt5($file) { $arr = pathinfo($file); return $arr['extension']; //或者这样return pathinfo($file,PATHINFO_EXTENSION); }

function getExt6($file){ preg_match("/(gif | jpg | png)$/",$file,$match); $match=$match[0]; }

function getExt7($file){ $match=preg_replace("/.*\.(\w+)/" , "\\1" ,$file); echo $match; }