Book Image

Mastering Julia - Second Edition

By : Malcolm Sherrington
Book Image

Mastering Julia - Second Edition

By: Malcolm Sherrington

Overview of this book

Julia is a well-constructed programming language which was designed for fast execution speed by using just-in-time LLVM compilation techniques, thus eliminating the classic problem of performing analysis in one language and translating it for performance in a second. This book is a primer on Julia’s approach to a wide variety of topics such as scientific computing, statistics, machine learning, simulation, graphics, and distributed computing. Starting off with a refresher on installing and running Julia on different platforms, you’ll quickly get to grips with the core concepts and delve into a discussion on how to use Julia with various code editors and interactive development environments (IDEs). As you progress, you’ll see how data works through simple statistics and analytics and discover Julia's speed, its real strength, which makes it particularly useful in highly intensive computing tasks. You’ll also and observe how Julia can cooperate with external processes to enhance graphics and data visualization. Finally, you will explore metaprogramming and learn how it adds great power to the language and establish networking and distributed computing with Julia. By the end of this book, you’ll be confident in using Julia as part of your existing skill set.
Table of Contents (14 chapters)

typealias and unions

It is often convenient to introduce a new name for an already expressible type, and for this, Julia provides a typealias mechanism.

In version 1.0 onward, the syntax has changed and now uses the following form:

julia> const Vct{T} = Array{T,1}
Array{T,1} where T
julia> const Mtx{T} = Array{T,2}
Array{T,2} where T

Type aliases are useful when defining an umbrella type as a union of simpler ones.

Union types are extensively used in Base, and there are many examples in the code listing here:

julia> const Signed64 = Union{Int8, Int16, Int32, Int64}
Union{Int16, Int32, Int64, Int8}
julia> const Unsigned64 = Union{UInt8, UInt16, UInt32, UInt64}
Union{UInt16, UInt32, UInt64, UInt8}
julia> const Integer64 = Union{Signed64,Unsigned64}
Union{Sigend64,Unsigned64}

Recall that in our vehicle type, we provided contact details such as name, email, and phone type. However, alternatively, it might be more appropriate to use a postal address. To accommodate...