Book Image

Learning Julia

By : Anshul Joshi, Rahul Lakhanpal
Book Image

Learning Julia

By: Anshul Joshi, Rahul Lakhanpal

Overview of this book

Julia is a highly appropriate language for scientific computing, but it comes with all the required capabilities of a general-purpose language. It allows us to achieve C/Fortran-like performance while maintaining the concise syntax of a scripting language such as Python. It is perfect for building high-performance and concurrent applications. From the basics of its syntax to learning built-in object types, this book covers it all. This book shows you how to write effective functions, reduce code redundancies, and improve code reuse. It will be helpful for new programmers who are starting out with Julia to explore its wide and ever-growing package ecosystem and also for experienced developers/statisticians/data scientists who want to add Julia to their skill-set. The book presents the fundamentals of programming in Julia and in-depth informative examples, using a step-by-step approach. You will be taken through concepts and examples such as doing simple mathematical operations, creating loops, metaprogramming, functions, collections, multiple dispatch, and so on. By the end of the book, you will be able to apply your skills in Julia to create and explore applications of any domain.
Table of Contents (17 chapters)
Title Page
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
8
Data Visualization and Graphics

Expressions and macros


Metaprogramming is fun, and Julia definitely has one of the best metaprogramming features compared with some of its rivals. The initial cues and inspiration have been taken from Lisp, and similarly to Lisp, Julia is written in Julia itself—or in other words, Julia is homoiconic.

To explain how Julia interprets a code, here is a small code snippet:

julia> code = "println(\"hello world \")"
"println(\"hello world \")"

julia> expression = parse(code)
:(println("hello world "))

julia> typeof(expression)
Expr

Here, we have simply passed a normal Julia code println("hello world") as a string to the function parse. This function, in turn, takes this piece of string and converts it into a data type called Expr, which is evident from the preceding code.

To see what's inside this Expr type of data closely, we can dig deeper:

julia> fieldnames(expression)
3-element Array{Symbol,1}:
 :head
 :args
 :typ 

julia> expression.args
2-element Array{Any,1}:
 :println    ...