Book Image

Julia 1.0 Programming - Second Edition

By : Ivo Balbaert
Book Image

Julia 1.0 Programming - Second Edition

By: Ivo Balbaert

Overview of this book

The release of Julia 1.0 is now ready to change the technical world by combining the high productivity and ease of use of Python and R with the lightning-fast speed of C++. Julia 1.0 programming gives you a head start in tackling your numerical and data problems. You will begin by learning how to set up a running Julia platform, before exploring its various built-in types. With the help of practical examples, this book walks you through two important collection types: arrays and matrices. In addition to this, you will be taken through how type conversions and promotions work. In the course of the book, you will be introduced to the homo-iconicity and metaprogramming concepts in Julia. You will understand how Julia provides different ways to interact with an operating system, as well as other languages, and then you'll discover what macros are. Once you have grasped the basics, you’ll study what makes Julia suitable for numerical and scientific computing, and learn about the features provided by Julia. By the end of this book, you will also have learned how to run external programs. This book covers all you need to know about Julia in order to leverage its high speed and efficiency for your applications.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell

Exception handling

When executing a program, abnormal conditions can occur that force the Julia runtime to throw an exception or error, show the exception message and the line where it occurred, and then exit. For example (follow along with the code in Chapter 4\errors.jl):

  • Using the wrong index for an array, for example, arr = [1,2,3]and then asking for arr[0] causes a program to stop with ERROR: BoundsError()
  • Calling sqrt() on a negative value, for example, sqrt(-3) causes ERROR: DomainError: sqrt will only return a complex result if called with a complex argument, try sqrt(complex(x)); the sqrt(complex(-3)) function gives the correct result 0.0 + 1.7320508075688772im
  • A syntax error in Julia code will usually result in LoadError

Similar to these, there are 18 predefined exceptions that Julia can generate (refer to They are all derived from a base type, Exception.

How can you signal an error condition yourself...