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

Understanding HTTP responses

The result of the HTTP.get invocation is an object that closely mirrors a raw HTTP response. The package makes our lives easier by extracting the raw HTTP data and neatly setting it up in a data structure, which makes manipulating it a breeze.

Let's take a look at its properties (or fields in Julia's lingo):

julia> fieldnames(typeof(resp)) 
(:version, :status, :headers, :body, :request)

The fieldnames function accepts a type as its argument and returns a tuple containing the names of the fields (or properties) of the argument. In order to get the type of a value, we can use the typeof function, like in the previous example.

Right! The status, headers, and body fields should by now sound familiar. The version field represents the version of the HTTP protocol (the HTTP/1.1 part in the first line of the response). Most web servers on the internet today use version 1.1 of the protocol, but a new major version, 2.0, is almost ready for wide deployment. Finally, the...