rustHow to replace strings using Rust regex?

Rust regex can be used to replace strings in a variety of ways. The replace method can be used to replace all occurrences of a pattern with a given string. For example:

let re = Regex::new(r"(\w+)").unwrap();
let before = "Hello World";
let after = re.replace_all(before, "Goodbye");
println!("{}", after);

Output example

GoodbyeGoodbye

The code above uses the Regex::new method to create a new Regex object, which is then used to call the replace_all method. This method takes two arguments: the string to be replaced and the string to replace it with. In this case, all occurrences of the pattern (\w+) are replaced with the string Goodbye.

Alternatively, the replace_all method can also take a closure as its second argument. This closure can be used to perform more complex replacements, such as replacing each occurrence of a pattern with a different string. For example:

let re = Regex::new(r"(\w+)").unwrap();
let before = "Hello World";
let after = re.replace_all(before, |caps: &Captures| {
    let word = caps[1].to_string();
    match word.as_str() {
        "Hello" => "Goodbye".to_string(),
        "World" => "Universe".to_string(),
        _ => word,
    }
});
println!("{}", after);

Output example

GoodbyeUniverse

In this example, the closure takes a Captures object as its argument, which contains the matched pattern. The closure then uses a match expression to check the matched pattern and return the appropriate replacement string.

Helpful links

• Rust Regex Documentation
• Rust Regex Tutorial

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