The Pandas workbench

The Pandas app is a Python editor that runs in WebAssembly (Pyodide). When the status line says pandas is ready, these names already exist:

• pd — pandas
• np — NumPy

You do not write import pandas as pd unless you want to. It does not hurt if you do.

Run code

Paste into the editor and press Ctrl+Enter (Windows/Linux) or Cmd+Enter (macOS). The console below the editor is stdout. Use print.

print("pandas", pd.__version__)
print("numpy", np.__version__)
print(pd.Series([1, 2, 3], name="n"))

You should see a version pair and a 3-row Series.

Files live in /uploads

Click Add files and choose a CSV, Excel workbook, or JSON file. After that:

import os

print(os.listdir("/uploads"))

Readable paths:

• sales.csv
• /uploads/sales.csv

If a name is missing from that listing, attach it before you run read_csv.

Drop a .py file on the editor to open it as code. Add files is for data.

Writes become download chips

out = pd.DataFrame({"n": [1, 2, 3]})
out.to_csv("demo.csv", index=False)
print("wrote demo.csv")
print(os.listdir("/uploads"))

After Run, click ↓ on the file chip. The workbench may also start a download. Nothing is uploaded to Swiftener’s servers.

Excel

.xlsx works once openpyxl has finished loading (the status line mentions it). Then:

# After you attach data.xlsx
# df = pd.read_excel("data.xlsx")
print("Use read_excel after openpyxl is ready.")

Reset, autosave, snippets

• Code autosaves in this browser.
• Reset restores the starter snippet — it does not delete /uploads.
• Snippets insert short recipes. This course’s blocks are longer on purpose.

Privacy

Python runs in this tab. Uploads live in IndexedDB on this device. Lesson pages on tutorials.swiftener.com are public HTML; they never see your DataFrames.