Polars

Polars: Blazingly fast DataFrames in Rust, Python, Node.js, R and SQL

Documentation: Node.js · Rust · Python · R

StackOverflow: Node.js · Rust · Python

Note: This library is intended to work only with server-side JS/TS (Node, Bun, Deno). For the browser, please see js-polars.

Usage

Importing

// esm
import pl from 'nodejs-polars';

// require
const pl = require('nodejs-polars');

Series

> const fooSeries = pl.Series("foo", [1, 2, 3])
> fooSeries.sum()
6

// a lot operations support both positional and named arguments
// you can see the full specs in the docs or the type definitions
> fooSeries.sort(true)
> fooSeries.sort({descending: true})
shape: (3,)
Series: 'foo' [f64]
[
        3
        2
        1
]
> fooSeries.toArray()
[1, 2, 3]

// Series are 'Iterables' so you can use javascript iterable syntax on them
> [...fooSeries]
[1, 2, 3]

> fooSeries[0]
1

DataFrame

>const df = pl.DataFrame(
...   {
...     A: [1, 2, 3, 4, 5],
...     fruits: ["banana", "banana", "apple", "apple", "banana"],
...     B: [5, 4, 3, 2, 1],
...     cars: ["beetle", "audi", "beetle", "beetle", "beetle"],
...   }
... )
> df.sort("fruits").select(
...     "fruits",
...     "cars",
...     pl.lit("fruits").alias("literal_string_fruits"),
...     pl.col("B").filter(pl.col("cars").eq(pl.lit("beetle"))).sum(),
...     pl.col("A").filter(pl.col("B").gt(2)).sum().over("cars").alias("sum_A_by_cars"),
...     pl.col("A").sum().over("fruits").alias("sum_A_by_fruits"),
...     pl.col("A").reverse().over("fruits").flatten().alias("rev_A_by_fruits")
...   )
shape: (5, 8)
┌──────────┬──────────┬──────────────┬─────┬─────────────┬─────────────┬─────────────┐
│ fruits   ┆ cars     ┆ literal_stri ┆ B   ┆ sum_A_by_ca ┆ sum_A_by_fr ┆ rev_A_by_fr │
│ ---      ┆ ---      ┆ ng_fruits    ┆ --- ┆ rs          ┆ uits        ┆ uits        │
│ str      ┆ str      ┆ ---          ┆ i64 ┆ ---         ┆ ---         ┆ ---         │
│          ┆          ┆ str          ┆     ┆ i64         ┆ i64         ┆ i64         │
╞══════════╪══════════╪══════════════╪═════╪═════════════╪═════════════╪═════════════╡
│ "apple"  ┆ "beetle" ┆ "fruits"     ┆ 11  ┆ 4           ┆ 7           ┆ 4           │
├╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┤
│ "apple"  ┆ "beetle" ┆ "fruits"     ┆ 11  ┆ 4           ┆ 7           ┆ 3           │
├╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┤
│ "banana" ┆ "beetle" ┆ "fruits"     ┆ 11  ┆ 4           ┆ 8           ┆ 5           │
├╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┤
│ "banana" ┆ "audi"   ┆ "fruits"     ┆ 11  ┆ 2           ┆ 8           ┆ 2           │
├╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌┤
│ "banana" ┆ "beetle" ┆ "fruits"     ┆ 11  ┆ 4           ┆ 8           ┆ 1           │
└──────────┴──────────┴──────────────┴─────┴─────────────┴─────────────┴─────────────┘

> df["cars"] // or df.getColumn("cars")
shape: (5,)
Series: 'cars' [str]
[
        "beetle"
        "beetle"
        "beetle"
        "audi"
        "beetle"
]

Node setup

Install the latest polars version with:

yarn add nodejs-polars   # yarn
npm i -s nodejs-polars   # npm
bun i -D nodejs-polars   # Bun

Releases happen quite often (weekly / every few days) at the moment, so updating polars regularly to get the latest bugfixes / features might not be a bad idea.

Minimum Requirements

Node version >=18
Rust version >=1.86 — only needed for development

Deno

In Deno modules you can import polars straight from npm:

import pl from "npm:nodejs-polars";

With Deno 1.37, you can use the display function to display a DataFrame in the notebook:

import pl from "npm:nodejs-polars";
import { display } from "https://deno.land/x/display@v1.1.2/mod.ts";

let response = await fetch(
  "https://cdn.jsdelivr.net/npm/world-atlas@1/world/110m.tsv",
);
let data = await response.text();
let df = pl.readCSV(data, { sep: "\t" });
await display(df)

With Deno 1.38, you only have to make the dataframe be the last expression in the cell:

import pl from "npm:nodejs-polars";
let response = await fetch(
  "https://cdn.jsdelivr.net/npm/world-atlas@1/world/110m.tsv",
);
let data = await response.text();
let df = pl.readCSV(data, { sep: "\t" });
df

Documentation

Want to know about all the features Polars supports? Read the docs!

Node

Installation: yarn add nodejs-polars or bun install nodejs-polars
Node documentation

Python

Installation: pip3 install polars
Python documentation
User guide

Rust

Rust documentation

Contribution

Want to contribute? Read our contribution guideline.

[Node]: compile polars from source

If you want a bleeding edge release or maximal performance you should compile polars from source.

Install the latest Rust compiler
Run npm|yarn install

Choose any of:

Fastest binary, very long compile times:

# generates a /bin directory with the compiled TS code and the Rust binary
cd nodejs-polars && yarn build && yarn build:ts

Debugging, fastest compile times but slow & large binary:

# generates a /bin directory with the compiled TS code and the Rust binary
cd nodejs-polars && yarn build:debug && yarn build:ts

Webpack configuration

To use nodejs-polars with Webpack please use node-loader and webpack.config.js