Rust and Cargo 1 cheatsheet

Rust and Cargo 1: Code patterns

7 common Rust and Cargo 1 tasks.

Hello world

The smallest runnable Rust program.

fn main() {
    println!("Hello, world!");
}

Define a type and derive common traits for debugging, copying and comparing.

#[derive(Debug, Clone, PartialEq)]
struct User {
    name: String,
    age: u32,
}

Return early with the error when a call fails.

fn read_config(path: &str) -> Result<String, std::io::Error> {
    let text = std::fs::read_to_string(path)?;
    Ok(text)
}

Handle every case of an enum or option.

match maybe_user {
    Some(user) => println!("Hello, {}", user.name),
    None => println!("No user"),
}

Chain iterator adapters, then collect the result.

let squares: Vec<u32> = (1..=5).map(|n| n * n).filter(|n| n % 2 == 1).collect();

Run async code with the Tokio runtime. Add it with cargo add tokio --features full.

#[tokio::main]
async fn main() {
    let body = reqwest::get("https://example.com").await.unwrap().text().await.unwrap();
    println!("{body}");
}

Insert values and read them back.

use std::collections::HashMap;

let mut scores = HashMap::new();
scores.insert("ada", 10);
let score = scores.get("ada").copied().unwrap_or(0);