rustHow to use look behind in regex in Rust?

Look behind is a feature of regular expressions that allows you to match a pattern only if it is preceded by another pattern. In Rust, look behind is supported by the regex crate.

Example code

use regex::Regex;

let re = Regex::new(r"(?<=foo)bar").unwrap();
let text = "foobar";

assert!(re.is_match(text));

Output example

true

Code explanation

• use regex::Regex: imports the Regex type from the regex crate.
• let re = Regex::new(r"(?<=foo)bar").unwrap(): creates a new Regex object from the given pattern. The ?<= syntax is used to specify a look behind pattern.
• let text = "foobar": creates a string to match against.
• assert!(re.is_match(text)): checks if the given string matches the regular expression.

Helpful links

• Regex crate documentation
• Look behind in Rust

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