How to escape curly braces in a format string in Rust

In Rust, strings typically use {} to insert the values of variables or expressions. Therefore, if you want to display curly braces themselves in the string, you need to escape them. This can be achieved by using double curly braces. Specifically, replace each { with {{ and each } with }}.

Here is a concrete example demonstrating how to escape curly braces in Rust:

rust
fn main() {
    // The string to display is: {hello}
    let msg = format!("{{hello}}");
    println!("{}", msg); // Output: {hello}

    // Using escaped curly braces in a more complex formatted string
    let err_code = 404;
    let error_msg = format!("Error {{code: {}}}", err_code);
    println!("{}", error_msg); // Output: Error {code: 404}
}

In this example, you can see how double curly braces {{ and }} are used to represent single curly braces { and } in the final string. Similarly, this escaping method is applicable even in strings containing variable interpolation.