# Greater Tables

Creating presentation quality tables from pandas dataframes is frustrating. It is hard to left-align text and right-align numbers using pandas `display` or `df.to_html`. The  `great_tables` package does a really nice job with pandas and polars dataframes but does not support indexes or TeX output. 

This package provides consistent HTML and TeX table output with flexible type-based formatting, and table rules. Neither output relies on the pandas `to_html` or `to_latex` functions. TeX output uses Tikz tables for very tight control over layout and grid lines. The package is designed for use in Jupyter Lab notebooks Quarto documents.

Usage: the main class `GT` should be subclassed to set appropriate defaults for your project. `sGT` provides an example.

The project is currently in **beta** status. HTML output is better developed than TeX.

## The Name

Obviously, the name is a play on the `great_tables` package. But, I have
been maintaining a set of macros called
[GREATools](https://www.mynl.com/old/GREAT/home.html) (generalized,
reusable, extensible actuarial tools) in VBA and Python since the late
1990s, and call all my macro packages "GREAT".

## Installation

``` python
pip install greater-tables
```

## Examples

The following example shows quite a hard table. It is formatted using
the `sGT` class, which is a subclass of `GT` with a few defaults set.

``` {.python .cell-code}
import pandas as pd
import numpy as np
from greater_tables import sGT
level_1 = ["Group A", "Group A", "Group B", "Group B", 'Group C']
level_2 = ['Sub 1', 'Sub 2', 'Sub 2', 'Sub 3', 'Sub 3']

multi_index = pd.MultiIndex.from_arrays([level_1, level_2])

start = pd.Timestamp.today().normalize()  # Today's date, normalized to midnight
end = pd.Timestamp(f"{start.year}-12-31")  # End of the year

hard = pd.DataFrame(
{'x': np.arange(2020, 2025, dtype=int), 
'a': np.array((100, 105, 2000, 2025, 100000), dtype=int),
'b': 10. ** np.linspace(-9, 9, 5),
'c': np.linspace(601, 4000, 5),
'd': pd.date_range(start=start, end=end, periods=5),
'e': 'once upon a time, risk is hard to define, not in Kansas anymore, neutrinos are hard to detect,  $\\int_\\infty^\\infty e^{-x^2/2}dx$ is a hard integral'.split(',')
}).set_index('x')
hard.columns = multi_index
sGT(hard, 'A hard table.')
```

![HTML output.](img/hard-html.png){width=66%}

![TeX output.](img/hard-tex.png){width=66%}

The output illustrates:

-   Quarto or Jupyter automatically the class's `_repr_html_` method (or
    `_repr_latex_` for pdf/TeX/Beamer output), providing seamless
    integration across different output formats.
-   Text is left-aligned, numbers are right-aligned.
-   The index is displayed, was detected as likely years, and formatted
    without a comma separator.
-   The first column of integers does have a comma thousands separator.
-   The second column of floats spans several orders of magnitude and is
    formatted using Engineering format, n for nano through G for giga.
-   The third column of floats is formatted with a comma separator and
    two decimals, based on the average absolute value.
-   The fourth column of date times is formatted as ISO standard dates
    (not date times).
-   The vertical lines separate the levels of the column multiindex. The
    subgroups are a little tricky.

More coming soon.

## Documentation

Available on
[readthedocs](https://greater-tables-project.readthedocs.io/en/latest).