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Dash

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Dash, a member of Plotly’s open-source tools, is a Open Source Python library for creating reactive, Web-based applications. Dash is a user interface library for creating analytical web applications. Those who use Python for data analysis, data exploration, visualization, modelling, instrument control, and reporting will find immediate use for Dash.

Why is Dash good?

  • Dash app code is declarative and reactive, which makes it easy to build complex apps that contain many interactive elements.
  • Every aesthetic element of the app is customizable
  • While Dash apps are viewed in the web browser, you do NOT have to write any Javascript or HTML. Dash provides a Python interface to a rich set of interactive web-based components.
  • Dash provides a simple reactive decorator for binding your custom data analysis code to your Dash user interface.
  • Through these two abstractions — Python components and reactive functional decorators — Dash abstracts away all of the technologies and protocols that are required to build an interactive web-based application.

Dash is simple enough that you can bind a user interface around your Python code in an afternoon. 👏

Architecture

Frontend and backend

Dash leverages the power of Flask and React, putting them to work for Python data scientists who may not be expert Web programmers.

  • Dash applications are web servers running Flask and communicating JSON packets over HTTP requests.
  • Dash’s frontend renders components using React.js
    • Dash components are Python classes that encode the properties and values of a specific React component and that serialize as JSON.
    • The full set of HTML tags, like <div/>, <img/>, <table/> are also rendered dynamically with React and their Python classes are available through the dash_html_component library.

CSS

CSS and default styles are kept out of the core library for modularity, independent versioning, and to encourage Dash App developers to customize the look-and-feel of their apps.

Data Visualization

Dash ships with a Graph component that renders charts with plotly.js.

  • built on top of D3.js (for publication-quality, vectorized image export) and WebGL (for high performance visualization)

  • declarative, open source, fast

  • supports a complete range of scientific, financial, and business charts.

  • Dash’s Graph element shares the same syntax as the open-source plotly.py library, so you can easily to switch between the two.

Open Source Repositories

Getting started

Deployment

If you want to share public Dash apps for free, you can deploy it on Heroku, one of the easiest platforms for deploying and managing public Flask applications.

Check out the tutorial: Deploying Dash Apps

Heroku

Heroku is a cloud platform as a service (PaaS) supporting several programming languages. It supports supports Java, Node.js, Scala, Clojure, Python, PHP, and Go. For this reason, Heroku is said to be a polyglot platform as it has features for a developer to build, run and scale applications in a similar manner across most languages.

Reference