{"id":21,"date":"2017-12-18T14:34:00","date_gmt":"2017-12-18T14:34:00","guid":{"rendered":"https:\/\/sandrock.co.za\/carl\/2017\/12\/18\/a-simple-gui-spreadsheet-in-less-than-100-lines-of-python\/"},"modified":"2026-08-11T06:22:40","modified_gmt":"2026-08-11T04:22:40","slug":"a-simple-gui-spreadsheet-in-less-than-100-lines-of-python","status":"publish","type":"post","link":"https:\/\/sandrock.co.za\/carl\/2017\/12\/a-simple-gui-spreadsheet-in-less-than-100-lines-of-python\/","title":{"rendered":"A simple GUI spreadsheet in less than 100 lines of Python"},"content":{"rendered":"\n

\nOriginal challenge: Standard library only<\/h2>\n\n\n\n

I set myself a little challenge to write a simple spreadsheet-like program in Python in less than 100 lines, using only the standard library.<\/p>\n\n\n\n

The code in this repository<\/a> manages it in 100 non-blank lines, including comments. 88 if you ignore the comments. The full code is also at the end of this post. Note: I have also redone the code in PyQT5. This is discussed after the tkinter code.<\/i><\/p>\n\n\n\n

This is what the program looks like when you run it:<\/p>\n\n\n\n

\"\"\/<\/a><\/figure>\n\n\n\n

\nYou can click on cells to edit their formulae and move around with the arrow keys. Formulae are evaluated once you press Return or navigate way from a cell. Every cell is evaluated as a Python expression. This means you don’t do the Excel thing of having formulae start with =. Everything is a fomula. So the formula in A2 in the screenshot above is valid and will evaluate to 1 once focus moves away from the cell. The math module is imported by default, so you can use sin and cos and so on. I use a very cheap and nasty call of eval to make it all work, which you should never do for production code.<\/p>\n\n\n\n

Other than using eval, I also play a little fast and loose with the way objects are allowed to touch each other in the code. I allow each cell to access all their siblings directly instead of going through an intermediary. I probably also break a couple of other OO rules along the way with the way the cells propagate their calculations when they are changed. But the whole code only took a couple of hours to write and it actually works.<\/p>\n\n\n\n

And now, here is the full code:<\/p>\n\n\n\n