function getExt($filename) {
//strrpos()函数查找字符串在另一个字符串中最后一次出现的位置。如果成功,则返回位置,否则返回 false。
$ext = strtolower ( substr ( $filename, strrpos ( $filename, '.' ) + 1 ) );
return $ext;
}
function getExt1($filename) {
//strrev()函数反转字符串
$str = strrev ( $filename );
$ext = strrev ( strtolower ( substr ( $str, 0, strpos ( $str, '.' ) ) ) );
return $ext;
}
function getExt2($filename) {
$ext = substr ( strrchr ( $filename, '.' ), 1 );
return $ext;
}
function getExt3($filename) {
$arr = explode ( '.', $filename );
$ext = strtolower ( end ( $arr ) );
return $ext;
}
function getExt4($filename) {
//array_reverse — 返回一个单元顺序相反的数组 explode() 字符分割
$arr = array_reverse ( explode ( '.', $filename ) );
$ext = strtolower ( $arr [0] );
return $ext;
}
function getExt5($filename) {
//split — 用正则表达式将字符串分割到数组中
$arr = split ( "\.", $filename );
$ext = strtolower ( array_pop ( $arr ) );
return $ext;
}
function getExt6($filename) {
$ext = strtolower ( pathinfo ( $filename, PATHINFO_EXTENSION ) );
return $ext;
}
function getExt7($filename) {
//pathinfo — 返回文件路径的信息
$arr = pathinfo ( $filename );
$ext = strtolower ( $arr ['extension'] );
return $ext;
}
function getExt8($filename) {
//preg_split — 用正则表达式分割字符串
$arr = preg_split ( '/\./', $filename );
$ext = strtolower ( $arr [count ( $arr ) - 1] );
return $ext;
}