Level Up Your Python Tables: Structure, Style, and Clarity with Great Tables

Great Tables is a fantastic Python library that lets you create beautiful display tables. This means transforming a raw data structure, like a Polars DataFrame, into a formatted, styled, beautified table suitable for reports and publishing insights.

You can get started with a single line of code:

import polars as pl
import polars.selectors as cs
from great_tables import GT, loc, style

coffee_sales = pl.read_ndjson("https://raw.githubusercontent.com/posit-dev/great-tables/4a11db5692a6e223b108dfcb73b39885652ccefb/docs/examples/_data/coffee-sales.ndjson")

GT(coffee_sales)

However, we believe that effective display tables go beyond the default with:

• A structure that makes them easy to read
• Well-formatted values to make data understandable
• Styling that draws the viewer’s attention to key takeaways

As “total fanatics about table display,” Michael Chow and Richard Iannone, the minds behind Great Tables, understand this deeply. In their latest video series, they walk through more advanced techniques to elevate your Great Tables with structure, formatting, and styling.

For instance, see how Great Tables code can transform our basic table:

Code

gt_leveled_up = (
    GT(coffee_sales)
    .tab_header(title="Coffee Equipment Sales for 2023")
    .tab_spanner(label="Revenue", columns=cs.starts_with("revenue"))
    .tab_spanner(label="Profit", columns=cs.starts_with("profit"))
    .cols_label(
        revenue_dollars="Amount",
        revenue_pct="Percent",
        profit_dollars="Amount",
        profit_pct="Percent",
        monthly_sales="Monthly Sales",
    )
    .fmt_currency(columns=cs.ends_with("dollars"), use_subunits=False)
    .fmt_percent(columns=cs.ends_with("pct"), decimals=0)
    .tab_style(
        style=style.fill(color="aliceblue"),
        locations=loc.body(columns=cs.starts_with("revenue")),
    )
    .tab_style(
        style=style.fill(color="papayawhip"),
        locations=loc.body(columns=cs.starts_with("profit")),
    )
    .tab_style(
        style=style.text(weight="bold"),
        locations=loc.body(rows=pl.col("product") == "Total"),
    )
    .fmt_nanoplot(columns="monthly_sales", plot_type="bar")
    .fmt_image(
        columns="icon",
        path="~/rrr/posit-web/wp-content/themes/Posit/markdown-blogs/level-up-great-tables/img/",
    )
)

gt_leveled_up

Coffee Equipment Sales for 2023
icon	product	Revenue		Profit		Monthly Sales
		Amount	Percent	Amount	Percent
	Grinder	$904,500	3%	$567,960	4%
	Moka pot	$2,045,250	7%	$181,080	1%
	Cold brew	$288,750	1%	$241,770	2%
	Filter	$404,250	1%	$70,010	0%
	Drip machine	$2,632,000	9%	$1,374,450	9%
	AeroPress	$2,601,500	9%	$1,293,780	9%
	Pour over	$846,000	3%	$364,530	2%
	French press	$1,113,250	4%	$748,120	5%
	Cezve	$2,512,500	9%	$1,969,520	13%
	Chemex	$3,137,250	11%	$817,680	6%
	Scale	$3,801,000	13%	$2,910,290	20%
	Kettle	$756,250	3%	$617,520	4%
	Espresso Machine	$8,406,000	29%	$3,636,440	25%
None	Total	$29,448,500	100%	$14,793,150	100%	None

Ready to level up your tables? Explore the series details below, or start watching it here!

Great Tables 1: Structure, Format, and Style

This video includes:

• Examples of nicely formatted tables
• An introduction to the display table workflow:
  • Structure for adding pieces like adding a title, column spanners, cleaning up column labels, creating row labels (stub), and grouping rows
  • Format for cleaning up the values within the data cells
  • Style for customizing the visual appearance of the table
• Other exciting features that enhance table display, such as nanoplots and images

Great Tables 2: Introducing Units Notation

This video includes:

• An introduction to unit notation and syntax
• Formatting methods
• Information on how to handle missing numbers
• Instructions on hiding columns

Great Tables 3: Data Color and Polishing

This video includes:

• Methods to transform a “wall of numbers” into a visually insightful heat map
• How to use Markdown for formatting
• Polars DataFrames and convenient column selectors
• Resources for further learning

Continue your Great Tables journey

We hope that you enjoy Michael and Rich’s video series! The fun doesn’t have to stop here.

• Explore the Great Tables package documentation.
• If you have questions, thoughts, or just want to chat, join the Great Tables Discord!