god — a grammar of data, for Python

One small vocabulary for manipulating tables, spelled the same way in Python, in R, and as plain text. A pipeline is checked whole before any of it runs, so a bad column is reported at the step that names it rather than failing partway through — or worse, not failing.

import pandas as pd
from god import *

sales = pd.read_csv("sales.csv")

sales >> keep(col.region == "West") \
      >> summarize(margin = total(col.margin), by = col.product)

The same sentence runs as plain text, byte-for-byte what you would paste into R or into a database:

run("""
sales
  then keep where [region] is "West"
  then summarize [margin] as total([margin]) by [product]
""")

And when you reach the edge of the vocabulary, it shows you the same pipeline in a tool you already know — show_as(pipeline, "pandas"), or "polars", "pyspark", "dplyr", "sql", "spark".

Installing

The distribution is grammar-of-data and the import is god — the PyPI name god was taken in 2016 by an unrelated package, and a distribution name and an import name are independent. Until the PyPI release lands, install a wheel built from the repository at https://github.com/psychometrician/god, which carries the engine inside it.

What is here

Any decision at all lives in the grammar, not here. This package finds a frame, hands over some text, runs the query it gets back, and returns a native frame.

What was checked about Python's operators

• |> is impossible. It does not tokenize, and Python's operator set is fixed by the grammar. No import hook fakes it, because that breaks the editor support a front end exists to provide.
• >> is available. Neither pandas nor polars defines __rshift__, so a bare frame falls through to __rrshift__. Verified by running it.
• | is refused. Both define __or__, and frame | verb never reaches the verb — it does an elementwise or and returns a frame of True. A silent wrong answer is the one outcome this project will not ship.

The manual, live in both languages, is at https://psychometrician.github.io/god-book/.