How to save and execute a python file?

Question

I do not prefer python-mode. I would like a generic way so that I can understand emacs.

I wish the file be saved and python file command then be run as if in a shell.

Answer 1

Use M-! (M-x shell-command) if you want to run a shell command, e.g. python file.py and print the output in a new buffer (*Shell Command Output*). That does not open a shell in a new buffer.

Use M-x shell to run a shell in a new buffer as pointed by @NickD.

Answer 2

You could use M-x compile with an appropriate compile-command value. e.g. as a file-local variable:

# -*- compile-command: "python file.py"; -*-

Emacs will prompt you to save (or not) the file before running the command.