Book Image

Rust Standard Library Cookbook

By : Jan Hohenheim, Daniel Durante
Book Image

Rust Standard Library Cookbook

By: Jan Hohenheim, Daniel Durante

Overview of this book

Mozilla’s Rust is gaining much attention with amazing features and a powerful library. This book will take you through varied recipes to teach you how to leverage the Standard library to implement efficient solutions. The book begins with a brief look at the basic modules of the Standard library and collections. From here, the recipes will cover packages that support file/directory handling and interaction through parsing. You will learn about packages related to advanced data structures, error handling, and networking. You will also learn to work with futures and experimental nightly features. The book also covers the most relevant external crates in Rust. By the end of the book, you will be proficient at using the Rust Standard library.
Table of Contents (12 chapters)

How it works...

As mentioned earlier, a HashMap is a collection to map one type of data to another. You do this by calling insert, and passing your key and its value [9]. If the key already had a value, it will be overwritten. This is why insert returns an Option: if there was a value before, it returns the old value [27], or otherwise None. If you want to make sure that you're not overwriting anything, make sure to check the result of contains_key [16] before inserting your value.

Both get and remove won't crash when called with an invalid key. Instead, they return a Result. In the case of remove, said Result contains the removed value.

As with most collections, you have the options to iterate over your data, by borrowing the key-value pairs[43], borrowing the keys while mutating the values [49], or moving them all [55]. Due to its nature, HashMap additionally allows you three more options: borrowing all values [74], mutating all values [80], or borrowing all keys [68]. You...