Python源文件中使用UTF-8编码

测试文件hello.py：

print "你好！"

运行一般都会报错：

File "hello.py", line 1
SyntaxError: Non-ASCII character '\xe4' in file hello.py on line 1, but no encoding declared; see http://www.Python.org/peps/pep-0263.html for details

加上编码注释就能运行：

# -*- coding: utf-8 -*-
print "你好！"