1 Introduction

This is a book created from Markdown and executable code.

See Knuth (1984) for additional discussion of literate programming.

import polars as pl
from datetime import datetime

df = pl.DataFrame(
    {
        "integer": [1, 2, 3],
        "date": [
            datetime(2025, 1, 1),
            datetime(2025, 1, 2),
            datetime(2025, 1, 3),
        ],
        "float": [4.0, 5.0, 6.0],
        "string": ["a", "b", "c"],
    }
)

print(df)

shape: (3, 4)
┌─────────┬─────────────────────┬───────┬────────┐
│ integer ┆ date                ┆ float ┆ string │
│ ---     ┆ ---                 ┆ ---   ┆ ---    │
│ i64     ┆ datetime[μs]        ┆ f64   ┆ str    │
╞═════════╪═════════════════════╪═══════╪════════╡
│ 1       ┆ 2025-01-01 00:00:00 ┆ 4.0   ┆ a      │
│ 2       ┆ 2025-01-02 00:00:00 ┆ 5.0   ┆ b      │
│ 3       ┆ 2025-01-03 00:00:00 ┆ 6.0   ┆ c      │
└─────────┴─────────────────────┴───────┴────────┘