Rust

17.6    Solutions

This section provides the code solutions for the practice exercises in Section 17.5. The code is largely self-explanatory; however, we have included comments and additional explanations wherever necessary to enhance understanding.

1. Matching telephone numbers without using \d shorthand

   use regex::Regex;fn main() {    let re = Regex::new(r"^\d......").unwrap();    let text = "My phone number is 816030 and the second phone number is 816694";    for cap in re.captures_iter(text) {        println!("match: {:?}", &cap[0]);    }}  

2. Understanding the question mark quantifier

   fn main() {    let re = Regex::new(r"_?\w+\.rs").unwrap();    let text = "file.rs _file.rs test.rs _test.rs";    for cap in re.find_iter(text) {        println!("{}", cap.as_str());    }}  

3. Using ...