Day 92 of 100 Days Coding Challenge: Python
Today I taught my app how to pack its bags and leave. In other words, I added import and export features. Sure, I could already copy-paste data or grab a screenshot with Greenshot, but sometimes you want your history neat and official—like a CSV for number crunching, a JSON for data nerds, or even a PNG snapshot to show off.
As an accountant, I’m a little obsessed with documentation. If it isn’t written down (preferably in triplicate), it might as well not exist. So this feature speaks to my soul: a one-click way to preserve the work I’ve done without juggling external tools. The first step? Adding Plotly’s Kaleido, which lets charts gracefully turn into PNGs instead of stubbornly staring back at you.
Today’s Motivation / Challenge
Why does this matter? Because sometimes you want to share your findings with others—or just keep a record for yourself—without re-running all the filters. Import/export turns the app into a portable historian. Think of it like saving leftovers: you can pack up today’s insights, reheat them later, and maybe even share with a friend.
Purpose of the Code (Object)
The code adds the ability to import data into the app and export filtered timelines as CSV, JSON, or PNG. That means you can save what you’re looking at, reload it later, or use it in another tool. It makes the app more than just an interactive toy—it becomes a proper record-keeper.
AI Prompt
I would like to add the following function:
Day 17 — Import/Export
- CSV/JSON importers
- Export filtered timeline as CSV + PNG snapshot
- Accept: round-trip a tiny dataset; PNG file downloads
Functions & Features
- Import datasets in CSV or JSON format.
- Export filtered results as CSV for spreadsheets.
- Save a PNG snapshot of the current timeline view.
- Round-trip: test importing and exporting to confirm nothing gets lost.
Requirements / Setup
You’ll need:
- Python 3.11
Installs:
pip install plotly kaleido streamlit
Minimal Code Sample
# Export timeline to PNG
fig.write_image(“timeline.png”)
# Export filtered data to CSV
df.to_csv(“filtered_timeline.csv”, index=False)
One saves your visualization as an image, the other exports your filtered data as a spreadsheet.
The Civilization Timeline Builder
Notes / Lessons Learned
Adding the helper functions was straightforward, but the placement of the sidebar UI block was trickier than expected. I initially dropped it in the wrong spot in streamlit_app.py, which triggered a spectacular cascade of errors. Once I moved it to sit neatly after the existing filters (year_range, selected_regions, selected_tags), everything clicked into place.
The PNG export was almost an afterthought—I nearly skipped it, exhausted after five hours of coding. But I pushed through, added it, and suddenly there it was: a crisp timeline image sitting on my desktop. Oddly enough, that little success gave me more motivation than any lecture on perseverance. Sometimes the best reward is seeing history look good in a file you can actually keep.
Optional Ideas for Expansion
- Add Excel export for people who live in spreadsheets.
- Bundle multiple outputs (CSV + PNG) into a single downloadable zip file.
- Create an auto-backup option so every filter session saves itself without asking.