1.1 运行python

python程序是由解释器来执行。通常只要在命令shell中输入python就可以启动解释器。解释器显示版权消息和>>>提示符，用户可以输入打印“Hello World”命令：

Python 2.7.3 (default, Apr 10 2012, 23:24:47) [MSC v.1500 64 bit (AMD64)] on win32

Type "copyright", "credits" or "license()" for more information.

>>> print "Hello World"

Hello World

>>>