Question

I am trying to run a python script in excel VBA like this:

Shell("python " & ActiveWorkbook.Path & "\CreateVolsurface.py -d ""10 Sep 12""")

but it does nothing. If I watch the task manager, a python process doesn’t even get created. If I debug and copy the string created in the code above and paste it into command prompt it runs perfectly.

The python script takes a date (as a string) as a parameter and creates an image file.

Any idea why this would not work or how I could debug it?

I’ve also tried this:

Shell ("python CreateVolsurface.py -d ""10 Sep 12""")

and this:

ret_val = Shell("python " & ActiveWorkbook.Path & "\CreateVolsurface.py -d ""10 Sep 12""", vbHide)

but they also do nothing.

---

The issue was that shell() in vba starts cmd.exe in it’s default folder and not in the active folder of the current workbook. In my python script I had relative path references which was an issue. To solve this I used the os module in my python script to change the current directory at the start.

Answer 1

Try specifying the path to python.exe, or you may need to add the path to your %PATH% environment variable.

Try the following to verify Shell is working and step through with the debugger:

ret_val = Shell("notepad.exe", vbNormalFocus)

If that works, then you should try specifying the path:

args = ActiveWorkbook.Path & "\CreateVolsurface.py -d ""10 Sep 12"""
ret_val = Shell("C:\python27\python.exe " & args)

If you need to check if python is in your %PATH% environment variable, the Process Explorer (procexp.exe) utility from sysinternals can show you all of the environment settings for a running process.