Calling python script from excel/vba

Question

Hello guys, I have a python code that reads 3 arguments (scalars) and a text files and then returns me a vector of double. I want to write a macro in vba to call this python code and write the results in one of the same excel sheet. I wanted to know what was the easiest way to do it, here are some stuffs that I found: - call the shell() function in vba but it doesn't seem so easy to get the return value. - register the python code as a COM object and call it from vba--> i don't know how to do that so if you have some examples it would be more than welcome - create a custom tool in a custom toolbox, in vba create a geoprocessing object and then addtoolbox and then we can use the custom tool directly via the geoprocessing object but this is something as well that I don't know how to do.. Any tips?

Answer 1

Do you have to call the Python code as a macro? You could use COM hooks within the Python script to direct Excel and avoid having to use another language:

import win32com.client

# Start Excel
xlApp = win32com.client.Dispatch( "Excel.Application" )
workbook = xlApp.Workbooks.Open( <some-file> )
sheet = workbook.Sheets( <some-sheet> )
sheet.Activate( )

# Get values
spam = sheet.Cells( 1, 1 ).Value

# Process values
...

# Write values
sheet.Cells( ..., ... ).Value = <result>

# Goodbye Excel
workbook.Save( )
workbook.Close( )
xlApp.Quit( )

Answer 2

Follow these steps carefully

1. Go to Activestate and get ActivePython 2.5.7 MSI installer.
   I had DLL hell problems with 2.6.x
2. Install in your Windows machine

3. once install is complete open Command Prompt and go to

   C:\Python25\lib\site-packages\win32comext\axscript\client

4. execute \> python pyscript.py you should see message Registered: Python

5. Go to ms office excel and open worksheet

6. Go to Tools > Macros > Visual Basic Editor
7. Add a reference to the Microsoft Script control
8. Add a new User Form. In the UserForm add a CommandButton

9. Switch to the code editor and Insert the following code

   Dim WithEvents PyScript As MSScriptControl.ScriptControl

   Private Sub CommandButton1_Click()
      If PyScript Is Nothing Then
          Set PyScript = New MSScriptControl.ScriptControl
          PyScript.Language = "python"
          PyScript.AddObject "Sheet", Workbooks(1).Sheets(1)
          PyScript.AllowUI = True
      End If
      PyScript.ExecuteStatement "Sheet.cells(1,1).value='Hello'"
   End Sub
   

Execute. Enjoy and expand as necessary