Rust Daily Learning - Day 9
Overview
Welcome to Day 9 of the Rust daily learning series! Today, we’ll focus on working with collections in Rust. Collections are data structures that store multiple values of the same type, allowing you to organize and manipulate your data effectively.
Vectors
A vector, or Vec, is a resizable array that can store elements of the same type. It is a widely used collection in Rust, as it provides a flexible way to store data.
To create a vector, you can use the vec! macro:
let v: Vec<i32> = vec![1, 2, 3, 4, 5];
You can also create an empty vector and push elements onto it:
let mut v = Vec::new();
v.push(1);
v.push(2);
v.push(3);
To access elements in a vector, you can use indexing or the get method:
let third: &i32 = &v[2];
let third: Option<&i32> = v.get(2);
Hash Maps
A hash map, or HashMap, is a key-value store that allows you to associate values with unique keys. To use a HashMap, you’ll need to import it from the std::collections module.
Here’s an example of creating and using a hash map:
use std::collections::HashMap;
let mut scores = HashMap::new();
scores.insert(String::from("Blue"), 10);
scores.insert(String::from("Yellow"), 50);
You can retrieve values from a hash map by using the get method:
let team_name = String::from("Blue");
let score = scores.get(&team_name);
Hash Sets
A hash set, or HashSet, is a collection of unique values, where each value can only occur once. Like HashMap, you’ll need to import HashSet from the std::collections module.
Here’s an example of creating and using a hash set:
use std::collections::HashSet;
let mut set: HashSet<i32> = HashSet::new();
set.insert(1);
set.insert(2);
set.insert(3);
You can check if a value is present in a hash set using the contains method:
if set.contains(&2) {
println!("Set contains the value 2");
}
That’s it for today’s lesson on working with collections in Rust. By understanding and utilizing vectors, hash maps, and hash sets, you can create more efficient and organized Rust programs. Keep learning, and see you in the next installment!