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Julia Programming Projects

You're reading from   Julia Programming Projects Learn Julia 1.x by building apps for data analysis, visualization, machine learning, and the web

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Product type Paperback
Published in Dec 2018
Publisher Packt
ISBN-13 9781788292740
Length 500 pages
Edition 1st Edition
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Author (1):
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Adrian Salceanu Adrian Salceanu
Author Profile Icon Adrian Salceanu
Adrian Salceanu
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Table of Contents (13) Chapters Close

Preface 1. Getting Started with Julia Programming FREE CHAPTER 2. Creating Our First Julia App 3. Setting Up the Wiki Game 4. Building the Wiki Game Web Crawler 5. Adding a Web UI for the Wiki Game 6. Implementing Recommender Systems with Julia 7. Machine Learning for Recommender Systems 8. Leveraging Unsupervised Learning Techniques 9. Working with Dates, Times, and Time Series 10. Time Series Forecasting 11. Creating Julia Packages 12. Other Books You May Enjoy

Dictionaries


The dictionary, called Dict, is one of Julia's most powerful and versatile data structures. It's an associative collection—it associates keys with values. You can think of a Dict as a look-up table implementation—given a single piece of information, the key, it will return the corresponding value.

Constructing dictionaries

Creating an empty instance of a Dict is as simple as the following:

julia> d = Dict() 
Dict{Any,Any} with 0 entries

The information between the curly brackets, {Any,Any}, represents the types of keys and values of the Dict. Thus, the concrete type of a Dict itself is defined by the type of its keys and values. The compiler will do its best to infer the type of the collection from the types of its parts. In this case, since the dictionary was empty, no information could be inferred, so Julia defaulted to Any and Any.

An {Any,Any} type of Dict allows us to add any kind of data, indiscriminately. We can use the setindex! method to add a new key-value pair to the...

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