__name__和__main的含义

if __name__ == "__main__":
    main()

This module represents the (otherwise anonymous) scope in which the interpreter’s main program executes — commands read either from standard input, from a script file, or from an interactive prompt. It is this environment in which the idiomatic “conditional script” stanza causes a script to run:

#此模块表示解释器的主程序执行的（否则为匿名）的范围，该命令读取标准输入，从脚本文件，或从交互式提示读取。正是这种环境，地道的“有条件的脚本”节使脚本运行：