Idiomatic Rust Snippets

How to call a function from a standard library:

use std::time::{SystemTime, UNIX_EPOCH};

fn main() {
    // Get the current system time
    match SystemTime::now().duration_since(UNIX_EPOCH) {
        Ok(n) => println!("Current time since UNIX EPOCH: {} seconds", n.as_secs()),
        Err(_) => println!("SystemTime before UNIX EPOCH!"),
    }
}

How to call a function from a library on Crates.io:

For external libraries, you can specify the external module in the Cargo.toml file.

use regex::Regex;

fn main() {
    // Create a regex pattern
    let re = Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();

    // Test if the pattern matches a string
    let date = "2023-10-05";
    if re.is_match(date) {
        println!("The date {} is in the correct format.", date);
    } else {
        println!("The date {} is not in the correct format.", date);
    }
}

Cargo.toml file content

[dependencies]
regex = "1.5"

Legacy solution for Rust 2015 edition or earlier

On the Rust file you may call extern crate PACKAGE_NAME to use an external library. This is a handy solution when you want to use Rust Playground like in this example below. Otherwise, you would get an error when you execute the file.

extern crate rand;
use rand::Rng;

fn main() {
    // Create a random number generator
    let mut rng = rand::thread_rng();

    // Generate a random number between 1 and 10
    let random_number: u32 = rng.gen_range(1..=10);

    println!("Random number: {}", random_number);
}