// 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"(?m)^(?:([^,\n]*),){3}([^\n]+)").unwrap();
let string = "null,admin,abc@site.ru,123
null,admin,cde@site.ru,345
,joe,efg@site.ru,333
,bob,ghj@site.ru,444
";
let substitution = "$1:$2";
// 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/