无法执行 Python 脚本

Question

I'm learning Python via 'Automate the Boring Stuff with Python' and I'm stuck on being able to execute my programs. I have the directory to my Python install added to my system environment variables (see below). When I run 'py' or 'python' from the terminal, it does bring up the Python window. However, when I try to run a specific program (for example, named pw.py) by typing 'py pw.py' or 'python pw.py' nothing happens. I have a shebang line in my program (#! python3). It looks like the window briefly tries to come up, but then nothing. Any ideas?

Here is the program:

#! python3
PASSWORDS = {'email': 'F7minlBDDuvMJuxESSKHFhTxFtjVB6','blog':'VmALvQyKAxiVH5G8v0lif1MLZF3sdt','luggage': '12345'}
import sys, pyperclip
if len(sys.argv) <2:
    print('Usage: python pw.py[account] -  copy account password')
    sys.exit()

account = sys.argv[1]  #first command line arg is the account name

if account in PASSWORDS:
    pyperclip.copy(PASSWORDS[account])
    print ('Password for ' + account + ' copied to clipboard.')
else:
    print ('There is no account named ' + account)

Path added

Using Admin Command Prompt (some of these are typos - hit enter too fast)

Answer 1

Looks like the problem is not with your "PATH". It is the way you execute the file.

Ideally, it should be,

python [python-file-name].py [command-line-arguments]

In my case it was,

python test.py email

In your case,

python [your_file_name.py] [email|blog|luggage]

This works like charm for me in both command line and IDE in both the usecases

ie with and without command line args. Just check if you are giving it the right way

Additional information :

From the screen shot, I see that you are using windows 10 (Correct me if am wrong). In windows 10, you have 2 command prompts.

1. One is for the regular users
2. The other one is in administrator mode.

python will not launch on regular command prompts.

I think you are using the regular mode command prompt. Please use the command prompt with admin access.

Check this link to see how to open cmd prompt as an admin. I think you can also open by right clicking on the windows icon.

If you still wanna use the regular cmd prompt you may also try python -i (interactive mode)

Answer 2

This struck me as weird when I came across this example in the same book and I thought it was a one off but he keeps using them. The shebang line is wrong in the book. It should be something like this:

#!/usr/bin/env python3

or

#!/usr/bin/python3

Or whatever your full path is to python3.

A shebang line must be #! and then whitespace and then a forward slash. No pathname expansion is done to find the interpreter (env or python3) so you must specify the full path. The space and interpreter name without its full path just won't work. In Appendix B at the end of the book, there is a short section that explains how to setup the shebang line properly, but yet this is at the end of the book. He does mention it in the first example, but being a beginner book, I'm sure this threw more than a few people off.

Curiously in Appendix B he states:

On Windows, the shebang line is #! python3.

This reflects the usage in the book, but as far as I know, shebang lines don't have any effect in Windows. Someone correct me if I'm wrong. I think the book should have used #!/usr/bin/env python3 in it's examples to save confusion.

Answer 3

My issue likes yours, but this is what i tried, and it worked.

First, in CMD, from any path, you can launch Python by typing python

like:

c:\>python

This means your windows path is correct.

Second, try to change your folder directory to the python code folder, in my case, it is c:\my documents\PythonCode. The command is:

cd "My Documents"\PythonCode

After this cmd, it should look like

C:\My Documents\PythonCode>

Last, type

python test.py

This should execute your py script.

So, in your case, you can try this:

c: 
cd c:\"Python Scripts"
python pw.py email

first line sets your directory to c drive second line sets your directory to Python Scripts folder third line execute your pw.py script.