Develop Data Visualization Interfaces in Python With Dash

How to Set Up Your Local Environment

To develop your app, you’ll need a new directory to store your code and data and a clean Python 3 virtual environment. To create those, follow the instructions below, choosing the version that matches your operating system.

If you’re using Windows, then open a command prompt and execute these commands:

c:\> mkdir avocado_analytics && cd avocado_analytics
c:\> c:\path\to\python\launcher\python -m venv venv
c:\> venv\Scripts\activate.bat

The first command creates a directory for your project and moves your current location there. The second command creates a virtual environment in that location. The last command activates the virtual environment. Make sure to replace the path in the second command with the path of your Python 3 launcher.

If you’re using macOS or Linux, then follow these steps from a terminal:

$ mkdir avocado_analytics && cd avocado_analytics
$ python3 -m venv venv
$ source venv/bin/activate

The first two commands perform the following actions:

1. Create a directory called avocado_analytics
2. Move your current location to the avocado_analytics directory
3. Create a clean virtual environment called venv inside that directory

The last command activates the virtual environment you just created.

Next, you need to install the required libraries. You can do that using pip inside your virtual environment. Install the libraries as follows:

(venv) $ python -m pip install dash==1.13.3 pandas==1.0.5

This command will install Dash and pandas in your virtual environment. You’ll use specific versions of these packages to make sure that you have the same environment as the one used throughout this tutorial. In addition to Dash, pandas will help you handle reading and wrangling the data you’ll use in your app.

Finally, you need some data to feed into your dashboard. You can download the data as well as the code you see throughout this tutorial by clicking the link below:

Save the data as avocado.csv in the root directory of the project. By now, you should have a virtual environment with the required libraries and the data in the root folder of your project. Your project’s structure should look like this:

avocado_analytics/
|
├── venv/
|
└── avocado.csv

You’re good to go! Next, you’ll build your first Dash application.

How to Build a Dash Application

For development purposes, it’s useful to think of the process of building a Dash application in two steps:

1. Define the looks of your application using the app’s layout.
2. Use callbacks to determine which parts of your app are interactive and what they react to.

In this section, you’ll learn about the layout, and in a later section, you’ll learn how to make your dashboard interactive. You’ll start by setting up everything you need to initialize your application and then you’ll define the layout of your app.