为什么`python main.py`（与`python main.py`不同）在Windows上可执行？

Question

# a.py
import b

# b.py
import a
print(1)

When I execute python a.py , import b works well but python a.py\ not.
I run it on Windows 11. I guess this happen's only on Windows, not linux.

When I check system path using sys.path , python a.py\ contains: (currentDir)/a.py , not (currentDir)

I wonder why python main.py\ is executable on Windows. And I guess it could induce some bugs for python-based programs.

Answer 1

On Windows, backslash is the path separator, thus python a.py\ tries to run a directory named "a.py" as a module (ie. it looks for a.py\__main__.py ). In your case, Python will error with a message that looks something like this:

can't open file 'c:\some\path\here\a.py\': [Errno 22] Invalid argument

because "a.py" is actually a file, so attempting to treat it as a directory fails.