Danfojs: powerful javascript data analysis toolkit
What is it?
Danfo.js is a javascript package that provides fast, flexible, and expressive data
structures designed to make working with "relational" or "labeled" data both
easy and intuitive. It is heavily inspired by Pandas library, and provides a similar API. This means that users familiar with Pandas, can easily pick up danfo.js.
Main Features
- Danfo.js is fast. It is built on Tensorflow.js, and supports tensors out of the box. This means you can convert Danfo data structure to Tensors.
- Easy handling of missing-data (represented as
NaN
) in floating point as well as non-floating point data - Size mutability: columns can be inserted/deleted from DataFrame
- Automatic and explicit alignment: objects can
be explicitly aligned to a set of labels, or the user can simply
ignore the labels and let
Series
, DataFrame
, etc. automatically
align the data for you in computations - Powerful, flexible groupby functionality to perform
split-apply-combine operations on data sets, for both aggregating
and transforming data
- Make it easy to convert Arrays, JSONs, List or Objects, Tensors and
differently-indexed data structures
into DataFrame objects
- Intelligent label-based slicing, fancy indexing, and querying of
large data sets
- Intuitive merging and joining data
sets
- Robust IO tools for loading data from flat-files
(CSV, Json, Excel, Data package).
- Powerful, flexible and intutive API for plotting DataFrames and Series interactively.
- Timeseries-specific functionality: date range
generation and date and time properties.
- Robust data preprocessing functions like OneHotEncoders, LabelEncoders, and scalers like StandardScaler and MinMaxScaler are supported on DataFrame and Series
Installation
There are three ways to install and use Danfo.js in your application
- For Nodejs applications, you can install the danfojs-node version via package managers like yarn and/or npm:
npm install danfojs-node
or
yarn add danfojs-node
For client-side applications built with frameworks like React, Vue, Next.js, etc, you can install the danfojs version:
npm install danfojs
or
yarn add danfojs
For use directly in HTML files, you can add the latest script tag from JsDelivr to your HTML file:
<script src="https://cdn.jsdelivr.net/npm/danfojs@1.1.2/lib/bundle.js"></script>
See all available versions here
Example Usage in the Browser
Run in Code Sandbox
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<script src="https://cdn.jsdelivr.net/npm/danfojs@1.1.2/lib/bundle.js"></script>
<title>Document</title>
</head>
<body>
<div id="div1"></div>
<div id="div2"></div>
<div id="div3"></div>
<script>
dfd.readCSV("https://raw.githubusercontent.com/plotly/datasets/master/finance-charts-apple.csv")
.then(df => {
df['AAPL.Open'].plot("div1").box()
df.plot("div2").table()
new_df = df.setIndex({ column: "Date", drop: true });
new_df.head().print()
new_df.plot("div3").line({
config: {
columns: ["AAPL.Open", "AAPL.High"]
}
})
}).catch(err => {
console.log(err);
})
</script>
</body>
</html>
Output in Browser:
Example usage in Nodejs
const dfd = require("danfojs-node")
const file_url = "https://web.stanford.edu/class/archive/cs/cs109/cs109.1166/stuff/titanic.csv"
dfd.readCSV(file_url)
.then(df => {
df.head().print()
df.describe().print()
console.log(df.shape);
console.log(df.columns);
df.ctypes.print()
df['Name'].print()
cols_2_remove = ['Age', 'Pclass']
df_drop = df.drop({ columns: cols_2_remove, axis: 1 })
df_drop.print()
let str_cols = df_drop.selectDtypes(["string"])
let num_cols = df_drop.selectDtypes(["int32", "float32"])
str_cols.print()
num_cols.print()
let new_vals = df['Fare'].round(1)
df_drop.addColumn("fare_round", new_vals, { inplace: true })
df_drop.print()
df_drop['fare_round'].round(2).print(5)
df_drop['Survived'].valueCounts().print()
df_drop.tail(10).print()
df_drop.isNa().sum().print()
}).catch(err => {
console.log(err);
})
Output in Node Console:
Notebook support
- You can use Danfo.js on Dnotebooks playground here
- VsCode nodejs notebook extension now supports Danfo.js. See guide here
Documentation
The official documentation can be found here
Danfo.js Official Book
We recently published a book titled "Building Data Driven Applications with Danfo.js". Read more about it here
Discussion and Development
Development discussions take place here.
Contributing to Danfo
All contributions, bug reports, bug fixes, documentation improvements, enhancements, and ideas are welcome. A detailed overview on how to contribute can be found in the contributing guide.
Licence MIT