Regex match numbers - capture using parentheses

• Regex

• captures

• (

• )

• regex::Captures

Cargo.toml

[package]
name = "regex-match-number"
version = "0.1.0"
edition = "2024"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
regex = "1.9.3"

Code

use regex::Regex;

fn main() {
    let text = String::from("There is the number 23 and another number here: 19");
    println!("{}", text);

    let re = Regex::new(r"[0-9]+").unwrap();

    let number = match re.captures(&text) {
        Some(value) => value,
        None => {
            println!("No match");
            return;
        }
    };
    println!("Number of matches: {}", number.len());
    println!("Full match: '{}'", &number[0]);

    // match the number that comes after colon (:)
    // but the match now includes the : as well
    let re = Regex::new(r": [0-9]+").unwrap();
    let number = match re.captures(&text) {
        Some(value) => value,
        None => {
            println!("No match");
            return;
        }
    };
    println!("Full match: '{}'", &number[0]);

    // Use parentheses to capture parts of the string
    let re = Regex::new(r": ([0-9]+)").unwrap();
    let number = match re.captures(&text) {
        Some(value) => value,
        None => {
            println!("No match");
            return;
        }
    };
    println!("Full match: '{}'", &number[0]);
    println!("Matched: '{}'", &number[1]);
}