Book Image

Julia Programming Projects

By : Adrian Salceanu
Book Image

Julia Programming Projects

By: Adrian Salceanu

Overview of this book

Julia is a new programming language that offers a unique combination of performance and productivity. Its powerful features, friendly syntax, and speed are attracting a growing number of adopters from Python, R, and Matlab, effectively raising the bar for modern general and scientific computing. After six years in the making, Julia has reached version 1.0. Now is the perfect time to learn it, due to its large-scale adoption across a wide range of domains, including fintech, biotech, education, and AI. Beginning with an introduction to the language, Julia Programming Projects goes on to illustrate how to analyze the Iris dataset using DataFrames. You will explore functions and the type system, methods, and multiple dispatch while building a web scraper and a web app. Next, you'll delve into machine learning, where you'll build a books recommender system. You will also see how to apply unsupervised machine learning to perform clustering on the San Francisco business database. After metaprogramming, the final chapters will discuss dates and time, time series analysis, visualization, and forecasting. We'll close with package development, documenting, testing and benchmarking. By the end of the book, you will have gained the practical knowledge to build real-world applications in Julia.
Table of Contents (19 chapters)
Title Page
Copyright and Credits
About Packt

Writing a basic web crawler – take one

We're now ready to write our first fully-fledged Julia program—a simple web crawler. This first iteration will make a request for Julia's Wikipedia page, will parse it and extract all the internal URLs, storing them in an Array.

Setting up our project

The first thing we need to do is to set up a dedicated project. This is done by using Pkg. It is a very important step as it allows us to efficiently manage and version the packages on which our program depends.

For starters, we need a folder for our software. Create one—let's call it WebCrawler. I'll use Julia to make it, but you do it however you like:

julia> mkdir("WebCrawler") 
julia> cd("WebCrawler/")

Now we can use Pkg to add the dependencies. When we start a new project, we need to initialise it. This is achieved with the following:

pkg> activate .

This tells Pkg that we want to manage dependencies in the current project as opposed to doing it globally. You will notice that the...