获取文件后缀名

1、js

var file_name = '传.奇.mp4';
var suffix = file_name .substr(file_name .lastIndexOf(".")); 
console.log(suffix);	//.mp4

2、PHP

$file_name = '传.奇.mp4';

echo '.'.end(explode('.',$file_name ));
//或
echo substr($file_name, strrpos( $file_name, '.'));

3、Python

    分离路径和文件名:           os.path.split()
    区分文件的名字和后缀:    os.path.splitext()

import os

file_path = "D:/data/传.奇.mp4"
(filepath, tempfilename) = os.path.split(file_path)
(filename, extension) = os.path.splitext(tempfilename)

print(file_path)        #D:/data/传.奇.mp4
print(tempfilename)     #传.奇.mp4
print(filename)         #传.奇
print(extension)        #.mp4