Run and execute a python script from VBA

Question

I'm trying to run a python script from my VBA module. I've tried pretty much every example I've seen on the internet and so for have had no luck. In the VBA module I also run a .bat file, and it works perfectly:

batchname = "U:\Backup Bat File.bat"

Shell batchname, vbNormalFocus

Next I need to run the python script, which is located in the same folder as the excel file. Right now I'm trying out this:

Dim Ret_Val

Dim args

args=Activeworkbook.Path & "\beps_output.py"

Ret_Val = Shell("C:\python34\python.exe" & args, vbNormalFocus)

It doesn't error out, but nothing happens. I'm a little confused at what the "Ret_Val" (return value?) does here, and why it isn't running.

Answer 1

This is running on my PC (Win 7 x64, python 2.7.9):

Sub runpython()
    Dim Ret_Val
    Dim args As String

    args = "W:\programming\python\other_py\sqrt.py"
    Ret_Val = Shell("C:\Program Files (x86)\python27\python.exe" & " " & args, vbNormalFocus)
    If Ret_Val = 0 Then
       MsgBox "Couldn't run python script!", vbOKOnly
    End If
End Sub

Ret_Val will be non-zero if the call succeeds, namely the processID of the launched command. Note that the command will run asynchronuously i.e. the VBA code will continue faster than the external command will terminate.

Answer 2

Try adding a space between exe program and file:

Ret_Val = Shell("C:\python34\python.exe " & args, vbNormalFocus)

Also, because Shell is a function that returns a value (variant type - double) with specified arguments, the returned value can be contained in a variable, here as you specify with Ret_Val. You can then add conditional logic and error handling using this value.