Is there a "main()" function in Python?

Question

In some languages, as in C, we have the function main() which is usually the default entry point of the program. There is something similar in Python?

Answer 1

There is no function main() in Python, at least not explicitly. What we have is '__main__' which is the name of the scope of the code executed in top-level, and is defined in __name__ the name of the module. O '__main__' is defined when the script is executed from the interactive terminal or called by the language interpreter.

You can get a "similar behavior" with the main() as follows:

if __name__ == '__main__':
   main()

This will prevent script content from running when imported:

import meuscript

So whatever’s on the block if will not run on import unless you do:

from meuscript import main
main()

and call the function main() directly.

See on documentation.

Answer 2

There is no python function main() as in C. However there is a native variable called __name__ (with two underlines before and after).

In python we have modules that can be executed indepedente or imported in another script. With the variable __name__ it is possible to know if the script is running through an import or directly.

If the script is running through an import, then the variable __name__ takes the name of the imported module. Now if the script is running directly, for example with the command python script.py, then the variable __name__ receives the amount __main__.

More detailed information on this link: https://blog.alura.com.br/o-que-significa-if-name-main-no-python/

Answer 3

Python is a language of script then it already begins to exist. In a certain way it exists, but not in the same way as C. It does not formally exist, the code that is found that is not inside a function is taken as a global function, the default input is the script that you have executed, from there it goes executing.

Answer 4

Speaking of application entry point, Python does not define a function for this.

The programs are interpreted from top to bottom, as is common in scripting languages. ³

Behold: https://stackoverflow.com/questions/36794098/designing-a-program-entry-point-in-python