// 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#"(?mx)# Keys are pretty much "any text before the '=' symbol"
(?P<key>[^=]+)
# Match the '=' symbol
=
(?P<value>
# Lazy match
.*?
# Look-ahead (don't move the "regex cursor", just "peek forward")
(?=
# Match a '_' that has no other '_' between it and the '=' character, or...
_[^_=\n]+=
|
# ... or the end of the line
$
)
)
# Actually "consume" the '_' character if it exists (or just match the end-of-line)
(?:_|$)"#).unwrap();
let string = "str=string_number=12345_device=phone_color=blue
color=aqua_marine_name=matt_number=123_456_879_lastname=blahblah";
let substitution = "\\1 = \\2\\n";
// 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/