book

Julia as a Second Language

by Erik Engheim

April 2023

Beginner to intermediate

400 pages

9h 18m

English

Manning Publications

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prefaceacknowledgmentsabout this bookWho should read this book?How this book is organizedAbout the codeliveBook discussion forumOther online resourcesabout the authorabout the cover illustration
1.1 What is Julia?1.1.1 Pros and cons of statically and dynamically typed languages1.2 Julia combines elegance, productivity, and performance1.3 Why Julia was created1.3.1 Scientists need the interactive programming that dynamically typed languages offer1.3.2 Developers in other fields also need the interactivity a dynamically typed language offers1.4 Julia’s higher performance solves the two-language problem1.5 Julia is for everyone1.6 What can I build with Julia?1.6.1 Julia in the sciences1.6.2 Nonscience uses of Julia1.7 Where Julia is less ideal1.8 What you will learn in this bookSummary
2.1 The Julia command line2.2 Using constants and variables2.2.1 Assigning and binding values to variables2.2.2 Using the ans variable2.2.3 What is a literal coefficient?2.3 Different number types and their bit length in Julia2.3.1 Writing numbers using different number formats2.4 Floating-point numbers2.4.1 Performing operations on integers and floating-point numbers2.5 Defining functions2.5.1 Storing function definitions in a file2.5.2 Working with functions in the REPL2.5.3 Functions everywhere2.5.4 Functions to work with numbers2.6 How to use numbers in practiceSummary
3.1 Navigation and trigonometry3.2 Boolean expressions3.2.1 Compound statements3.3 Looping3.3.1 Flowchart3.3.2 Making a mathematical table for the sine function3.3.3 Range objects3.3.4 For loops3.4 Multiline functions3.4.1 Implementing the sine trigonometric function3.5 Implementing factorial3.6 Factorial with recursion3.7 If statements3.7.1 If-else statements3.7.2 Elseif clause3.8 Throwing exceptions to handle errors3.9 Control flow vs. data flow3.10 Counting rabbits3.10.1 Base case3.10.2 Iteration vs. recursion3.10.3 To return or not returnSummary

4.1 Analyzing pizza sales4.2 Different types of arrays4.3 Performing operations on arrays4.4 Working with the statistics module4.5 Accessing elements4.6 Creating arrays4.7 Mapping values in an array4.8 Introducing characters and strings4.9 Storing pizza data in tuples4.10 Filtering pizzas based on predicates4.10.1 Combining higher-order functions4.11 Mapping and reducing an array4.11.1 Sine table with map and reduce4.12 Counting matches with Boolean arraysSummary
5.1 Making a pretty pizza sales table5.1.1 Print, println, and printstyled5.1.2 Printing multiple elements5.1.3 Printing multiple pizzas5.1.4 Align with lpad and rpad5.1.5 Adding lines5.2 Printing a trigonometric table5.3 Reading and writing pizza sales to CSV files5.3.1 Writing pizza sales to a file5.3.2 Reading pizza sales from a file5.4 Interacting with the userSummary
6.1 Parsing Roman numerals6.2 Using the Dict type6.3 Looping over characters6.4 Enumerating values and indices6.5 Explaining the conversion process6.6 Using dictionaries6.6.1 Creating dictionaries6.6.2 Element access6.7 Why use a dictionary?6.8 Using named tuples as dictionaries6.8.1 When do you use a named tuple?6.8.2 Tying it all togetherSummary
7.1 Creating composite types from primitive types7.2 Exploring type hierarchies7.3 Creating a battle simulator7.3.1 Defining warrior types7.3.2 Adding behavior to warriors7.3.3 Using multiple dispatch to invoke methods7.4 How Julia selects method to call7.4.1 Contrasting Julia’s multiple dispatch with object-oriented languages7.4.2 How is multiple dispatch different from function overloading?Summary
8.1 Building a simple rocket8.2 Maintaining invariants in your code8.3 Making objects with constructor functions8.4 Differences between outer and inner constructors8.5 Modeling rocket engines and payloads8.6 Assembling a simple rocket8.7 Creating a rocket with multiple stages and engines8.8 Launching a rocket into spaceSummary
9.1 Exploring Julia’s number promotion system9.2 Understanding number conversion9.3 Defining custom units for angles9.3.1 Defining angle constructors9.3.2 Defining arithmetic operations on angles9.3.3 Defining accessors to extract degrees, minutes, and seconds9.3.4 Displaying DMS angles9.3.5 Defining type conversions9.3.6 Making pretty literals9.3.7 Type promotionsSummary
10.1 The nothing object10.2 Using nothing in data structures10.2.1 What is a parametric type?10.2.2 Using union types to end the wagon train10.3 Missing values10.4 Not a number10.5 Undefined data10.6 Putting it all togetherSummary
11.1 UTF-8 and Unicode11.1.1 Understanding the relation between code points and code units11.2 String operations11.2.1 Converting from camel case to snake case11.2.2 Converting between numbers and strings11.2.3 String interpolation and concatenation11.2.4 sprintf formatting11.3 Using string interpolation to generate code11.4 Working with nonstandard string literals11.4.1 DateFormat strings11.4.2 Raw strings11.4.3 Using regular expressions to match text11.4.4 Making large integers with BigInt11.4.5 MIME typesSummary
12.1 Defining interfaces12.2 Propellant tank interface example12.3 Interfaces by convention12.4 Implementing engine cluster iteration12.4.1 Making clusters iterable12.5 Implementing rocket stage iteration12.5.1 Adding support for map and collect12.6 Comparison of linked lists and arrays12.6.1 Adding and removing elements12.7 Utility of custom typesSummary
13.1 What kind of problems can sets help solve?13.2 What is a set?13.2.1 Comparing properties of sets and arrays13.3 How to use set operations13.4 How to use sets in your code13.5 Searching for products using set operations13.5.1 Defining and using enumerations13.5.2 Creating test data to perform queries on13.5.3 Searching for screws13.5.4 Putting screw objects into sets13.5.5 Looking up screws using dictionaries13.6 Search in bug tracker using sets13.7 Relational databases and setsSummary
14.1 Vectors and matrices in mathematics14.2 Constructing a matrix from rows and columns14.3 The size, length, and norm of an array14.4 Slicing and dicing an array14.5 Combining matrices and vectors14.6 Creating matricesSummary
15.1 How does functional programming differ from object-oriented programming?15.2 How and why you should learn to think functionally15.3 Avoid deeply nested calls with function chaining15.3.1 Understanding anonymous functions and closures15.3.2 Using the pipe operator |>15.3.3 Conveniently produce new functions using partial application15.4 Implementing Caesar and substitution ciphers15.4.1 Implementing the Caesar cipher15.4.2 Implementing substitution ciphers15.5 Creating a cipher-algorithm-agnostic service15.6 Building an encryption service using object-oriented programming15.7 Building an encryption service using functional programming15.7.1 Defining a functional Caesar cipher15.7.2 Defining a functional substitution cipher15.7.3 Implementing a functional password-keeper serviceSummary
16.1 Setting up a work environment16.1.1 Using a package in the REPL16.1.2 How modules relate to packages16.2 Creating your own package and module16.2.1 Generating a package16.2.2 Adding code to your package16.3 Modifying and developing a package16.4 Tackling common misconceptions about modules16.5 Testing your packageSummary
17.1 Introducing Julia’s I/O system17.2 Reading data from a process17.3 Reading and writing to a socket17.4 Parsing a CSV file17.4.1 Loading rocket engine data17.4.2 Saving rocket engine dataSummary
18.1 Defining parametric methods18.2 Defining parametric types18.3 Type safety benefits from parametric types18.4 Performance benefits from parametric types18.5 Memory benefits of parametric typesSummary
A.1 Downloading JuliaA.2 Installing JuliaA.3 On LinuxA.3.1 On macOSA.3.2 On WindowsA.4 Configuring JuliaA.4.1 On Linux and macOSA.4.2 On WindowsA.5 Running JuliaA.6 Julia REPL ModesA.7 Installing third-party packages
B.1 Different number types and their bit lengthsB.2 Overflow and signed and unsigned numbersB.3 Floating-point numbers

Overview

Learn the awesome Julia programming language by building fun projects like a rocket launcher, a password keeper, and a battle simulator.

Julia as a Second Language covers:

Data types like numbers, strings, arrays, and dictionaries
Immediate feedback with Julia’s read-evaluate-print-loop (REPL)
Simplify code interactions with multiple dispatch
Sharing code using modules and packages
Object-oriented and functional programming styles

Julia as a Second Language introduces Julia to readers with a beginning-level knowledge of another language like Python or JavaScript. You’ll learn by coding engaging hands-on projects that encourage you to apply what you’re learning immediately. Don’t be put off by Julia’s reputation as a scientific programming language—there’s no data science or numerical computing knowledge required. You can get started with what you learned in high school math classes.

About the Technology
Originally designed for high-performance data science, Julia has become an awesome general purpose programming language. It offers developer-friendly features like garbage collection, dynamic typing, and a flexible approach to concurrency and distributed computing. It is the perfect mix of simplicity, flexibility and performance.

About the Book
Julia as a Second Language introduces Julia by building on your existing programming knowledge. You’ll see Julia in action as you create a series of interesting projects that guide you from Julia’s basic syntax through its advanced features. Master types and data structures as you model a rocket launch. Use dictionaries to interpret Roman numerals. Use Julia’s unique multiple dispatch feature to send knights and archers into a simulated battle. Along the way, you’ll even compare the object-oriented and functional programming styles–Julia supports both!

What's Inside

Data types like numbers, strings, arrays, and dictionaries
Immediate feedback with Julia’s read-evaluate-print-loop (REPL)
Simplify code interactions with multiple dispatch
Share code using modules and packages

About the Reader
For readers comfortable with another programming language like Python, JavaScript, or C#.

About the Author
Erik Engheim is a writer, conference speaker, video course author, and software developer.

Quotes
Helped kickstart my use of Julia for serious projects. It’s a solid review of the core language features that doesn’t get bogged down on programming fundamentals you already know.
- Jonathan Owens, GE Global Research

Everything you need to learn Julia.
- Amanda Debler, Schaeffler Technologies

Julia for seasoned programmers.
- Kevin Cheung, Carleton University

Perfect for anyone who needs to learn Julia but doesn’t know where to start.
- Simone Sguazza, University of Applied Sciences and Arts of Southern Switzerland