我必须在我的python代码中有main函数吗？

Question

Can I write a python code with a bunch of functions but without a main function. The purpose of this script is for other scripts to import some of the functions from. I will call it setvar_general.py or something which will be imported by a series of other setvar_x scripts. While these setvar_x do more specific things, setvar_general does not do any thing other than providing building blocks. Therefore there is not need for defining a main function in setvar_general.py.

I guess it all comes down to the question "do I have to have main function"?

Answer 1

You do not have to have a main function in Python and writing separate files without a main function, to be imported into other programs, is the normal and correct way of doing Python programming.

When a Python file is loaded (either using import or by getting executed from the command line) each statement in the program is executed at that time . Statements that are def or class statements create a function or class definition for later use. Statements that are are not inside a def or class will be executed right away.

Therefore, the equivalent of a main() function in other languages is actually the set of executable statements found in your file. If you limit these to def and/or class statements, you will get the effect you want.