How to do it...

1. Open the Cargo.toml file that was generated earlier for you

2. Under [dependencies], add the following line:

regex = "0.2"

3. If you want, you can go to regex's crates.io page (https://crates.io/crates/regex) to check for the newest version and use that one instead

4. In the bin folder, create a file called regex.rs

5. Add the following code and run it with cargo run --bin regex:

1   extern crate regex;
2
3   fn main() {
4     use regex::Regex;
5     // Beginning a string with 'r' makes it a raw string,
6     // in which you don't need to escape any symbols
7     let date_regex =
        Regex::new(r"^\d{2}.\d{2}.\d{4}$").expect("Failed
          to create regex");
8     let date = "15.10.2017";
9     // Check for a match
10    let is_date = date_regex.is_match(date);
11    println!("Is '{}' a date? {}", date, is_date);
12
13    // Let's use capture groups now
14    let date_regex = Regex::new(r"(\d{2}).(\d{2})
        .(\d{4})").expect("Failed to create regex");
15    let text_with_dates = "Alan Turing was born on 23.06.1912 and
          died on 07.06.1954. \
16      A movie about his life called 'The Imitation Game' came out
          on 14.11.2017";
17    // Iterate over the matches
18    for cap in date_regex.captures_iter(text_with_dates) {
19      println!("Found date {}", &cap[0]);
20      println!("Year: {} Month: {} Day: {}", &cap[3], &cap[2],
          &cap[1]);
21    }
22    // Replace the date format
23    println!("Original text:\t\t{}", text_with_dates);
24    let text_with_indian_dates =
        date_regex.replace_all(text_with_dates, "$1-$2-$3");
25    println!("In indian format:\t{}", text_with_indian_dates);
26
27    // Replacing groups is easier when we name them
28    // ?P<somename> gives a capture group a name
29    let date_regex = Regex::new(r"(?P<day>\d{2}).(?P<month>\d{2})
        .(?P<year>\d{4})")
30      .expect("Failed to create regex");
31    let text_with_american_dates =
        date_regex.replace_all(text_with_dates,
          "$month/$day/$year");
32    println!("In american format:\t{}", 
      text_with_american_dates);
33    let rust_regex = Regex::new(r"(?i)rust").expect("Failed to
        create regex");
34    println!("Do we match RuSt? {}", 
      rust_regex.is_match("RuSt"));
35    use regex::RegexBuilder;
36    let rust_regex = RegexBuilder::new(r"rust")
37      .case_insensitive(true)
38      .build()
39      .expect("Failed to create regex");
40    println!("Do we still match RuSt? {}",
        rust_regex.is_match("RuSt"));
41  }