Writing Python code within an Excel workbook to fill cells

This page has 0 threads | Add post

Blogs

Many people around the world enjoy and benefit from our blogs. If you're one of them - and can afford to - please make a small donation to help keep this and future blogs, exercises, skills assessment tests, tips, tutorials and videos freely available to everyone!

Calling Python code from within Excel, and the vast functionality it unlocks Part one of a five-part series of blogs
Excel and Python are getting ever more intertwined: you can now use the PY function to write (and call) Python code from within an Excel worksheet Writing Python code within an Excel workbook to fill cells (this blog) Returning dataframes from Python code to fill Excel ranges Manipulating images in Python within Excel How does Python reference modules within Excel? Creating and calling your own functions in Python

Calling Python code from within Excel, and the vast functionality it unlocks

Part one of a five-part series of blogs

Excel and Python are getting ever more intertwined: you can now use the PY function to write (and call) Python code from within an Excel worksheet

Writing Python code within an Excel workbook to fill cells (this blog)
Returning dataframes from Python code to fill Excel ranges
Manipulating images in Python within Excel
How does Python reference modules within Excel?
Creating and calling your own functions in Python

Posted by Andy Brown on 27 October 2025

In this blog

How the basic PY function works
Referencing cells and ranges
Using the Python Editor sidebar
Using the Excel formula bar

The PY function (allowing you to run Python code from an Excel cell) has now migrated from Excel Labs into mainstream Excel:

You won't see it in the Excel function wizard, but you should be able to type =PY( to call Python code.

If your work involves analysing data in Excel, this ability to effortlessly call Python code from within a worksheet may well change your life. This blog will get you started, showing how to call basic code and how to work with dataframes, images, modules and custom functions. You can download an Excel workbook containing all of the examples here.

How the basic PY function works

Suppose you have a worksheet like this, and you want to show the total of the two numbers held in cells B1 and B2:

Sadly, you've forgotten how to create any Excel formuale, so will rely on Python code to add these two numbers together ...

Type =PY( into the cell to see this:

You're now ready to type in Python code.

Type in your Python code:

The intellisense and editor are pretty good. When you've finished you must press Ctrl + Enter to enter this code into the cell.

Notice that you don't use the return command at the end of the code, as you would if this were a Python function (doing so actually generates an error).

You'll see this while the formula calculates:

This shows that the Python code is running (for the above example it only appears for a split second).

You'll then see the result of running your code:

Who knew? 3 + 5 = 8.

Referencing cells and ranges

Cleverly, you can click on a cell or range of cells to include a reference to it in your Python code:

Here we're about to say which cells we want to sum.

Just like in normal functions, Excel will use range names wherever they exist:

Here we've given the block of selected cells a range name, so Excel uses this instead of the cell references.

Using the Python Editor sidebar

If your code contains an error when you press Ctrl + Enter the Python editor sidebar will automatically appear, but you can also invoke it by right-clicking on a cell and choosing this short-cut menu option:

Right-click on a Python code cell to show the Python editor.

You can then use this editor to make changes to your code in a fairly intuitive way:

You can scroll down to see all of your Python cells (as here), the cells containing errors or the Python cells you currently have selected, depending on your dropdown choice.

Using the Excel formula bar

It can be useful to press Ctrl + Shift + U when editing a Python formula in an Excel cell:

When editing a formula, press Shift + Ctrl + U .

You can then edit the formula in an extended formula bar:

So you now have 3 ways to edit Python code: in-cell, using the separate Python editor or in the formula bar. Out of the 3 options I think I prefer this last one, although there's not much to choose between them.

Now that we've seen how to call simple Python code, let's have a look at some examples using dataframes.

Parts of this blog
Writing Python code within an Excel workbook to fill cells (this blog) Returning dataframes from Python code to fill Excel ranges Manipulating images in Python within Excel How does Python reference modules within Excel? Creating and calling your own functions in Python

Some other pages relevant to the above blogs include:

This blog has 0 threads

Add a new post

ALL BLOGS

EXCEL BLOGS

EXCEL BLOGS

How the basic PY function works

Referencing cells and ranges

Using the Python Editor sidebar

Using the Excel formula bar

Head office

London

Manchester