Question

How to extract the number from the end of a string in Rust

Answer 1

use regex::Regex;

fn extract_last_number(s: &str) -> i32 {
    let re = Regex::new(r"\D+").unwrap();
    
    let parts: Vec<&str> = re.split(s).collect();
    
    parts.last().unwrap().parse::<i32>().unwrap()
}

fn main() {
    let s = "rust 84 programming1092";
    
    let n = extract_last_number(s);
    
    println!("{}", n);
}

  
  
  
/*
run:
  
1092
  
*/

 

70+ SQL courses for beginners and professionals

Answer 2

fn extract_last_number(s: &str) -> i32 {
    let mut i = s.len();

    while i > 0 && s.chars().nth(i - 1).unwrap().is_digit(10) {
        i -= 1;
    }

    s[i..].parse::<i32>().unwrap()
}

fn main() {
    let s = "rust 84 programming1092";

    let n = extract_last_number(s);

    print!("{}", n);
}

  
  
  
/*
run:
  
1092
  
*/

 

70+ SQL courses for beginners and professionals