When you run a Python script like helloworld.py
Command Execution :
You enter python hello_world.py in the terminal. The OS locates the Python interpreter and starts it, passing the script as an argument.
Interpreter Initialization :
The Python interpreter initializes, setting up:
Built-in modules (e.g., sys, os).
The _main_ module for the script's execution context.
The Global Interpreter Lock (GIL) for thread management.
Source Code Parsing :
The interpreter reads hello_world.py and checks for syntax errors. If errors exist, it halts and reports them.
Bytecode Compilation :
If no .pyc file exists (or it's outdated), the interpreter compiles the source code into bytecode (low-level, platform-independent instructions).
The AST (Abstract Syntax Tree) is generated as an intermediate step.
The bytecode is saved in a .pyc file (e.g., __pycache__/hello_world.cpython-39.pyc).
Bytecode Execution :
The Python Virtual Machine (PVM) executes the bytecode:
print("Hello, World!") is translated into bytecode instructions (e.g., LOAD_CONST, CALL_FUNCTION).
The PVM interprets these instructions, invoking the print function.
print internally uses C-level functions (via Python’s C API) to write the string to stdout , which eventually triggers OS system calls (e.g., write() on Unix).
Output Handling :
The OS routes the output to the terminal, displaying "Hello, World!".
Cleanup and Exit :
The interpreter deallocates resources (e.g., memory for the string).
Control returns to the OS, exiting with a status code (0 for success).
Auf dieser Seite können Sie das Online-Video When you run a Python script like helloworld.py mit der Dauer stunde minuten sekunde in guter Qualität ansehen, das der Benutzer LearnPy 08 März 2025 hochgeladen hat, den Link mit Freunden und Bekannten teilen, dieses Video wurde auf Youtube bereits 7 Mal angesehen und es wurde von 0 den Zuschauern gefallen. Viel Spaß beim Betrachtenden Zuschauern gefallen!
