if __name__ == '__main__'

if __name__ == '__main__':

• make a script both importable and executable
• Don't BiuBiu, show me your code :

# test.py
def main():
  print "we are in %s",%__name__
if __name__ == '__main__':
  main()

直接执行上述代码，将在屏幕上打印we are in main 说明if语句内容被执行，调用了main();
倘若我们在另一个模块中导入该模块时，其执行结果为：we are in test
-- 如果我们是直接执行某个.py文件，该文件中那么"__name__"= __main__