// include the latest version of the regex crate in your Cargo.toml
extern crate regex;
use regex::Regex;
fn main() {
let regex = Regex::new(r"(?mi)^a\..*?\Kain't").unwrap();
let string = "For instance, if in the text below I wanted to replace \"ain't\" with \"is not\" for lines beginning \"a.\" but not \"b.\":
a. This ain't a worm.
b. No, it ain't.
a. Ain't a snake, either.
b. No, ain't one of them.
a. ain't multiple ain't and more ain't
";
let substitution = "is not";
// result will be a String with the substituted value
let result = regex.replace_all(string, substitution);
println!("{}", result);
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Rust, please visit: https://docs.rs/regex/latest/regex/