// 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"(?sm)(?(?=.*?^\h*param\h*=\N*).*?\K^\h*param\h*=\N*|.*?\K^\h*#+\h*param\h*=\N*)").unwrap();
let string = " ### param = 1
# param = 2
# param = 3
param = 4
# param = 5
";
let substitution = "${2}7";
// result will be a String with the substituted value
let result = regex.replace(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/