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

Creating functions


Functions in Julia are declared with the function keyword, which is then followed by the body of the function. Another keyword, end, puts or marks a logical end to the function in general. The syntax of defining a function can be summarized as:

function name()
        …
   body
      …
end

The function's name has to be followed by a bracket (). Failing to do so will result in an error. People coming from languages such as Python may find it a little different, but it becomes easy as you start coding in Julia. Let's just have a look at how a function is defined and used inside Julia's REPL:

julia> function greet()
           println("hello world")
       end
greet (generic function with 1 method)

julia> greet()
hello world

Here is what the official documentation says about functions:

"A function is an object that maps a tuple of argument values to a return value."

To present a better example of how we can make useful functions and how to call them, we have created a function...