22.1.1. 验证并提取电子邮件登录信息
验证电子邮件地址的格式是否正确,并提取 @ 符号之前的所有内容。
use lazy_static::lazy_static; use regex::Regex; fn extract_login(input: &str) -> Option<&str> { lazy_static! { static ref RE: Regex = Regex::new(r"(?x) ^(?P<login>[^@\s]+)@ ([[:word:]]+\.)* [[:word:]]+$ ").unwrap(); } RE.captures(input).and_then(|cap| { cap.name("login").map(|login| login.as_str()) }) } fn main() { assert_eq!(extract_login(r"I❤email@example.com"), Some(r"I❤email")); assert_eq!( extract_login(r"sdf+sdsfsd.as.sdsd@jhkk.d.rl"), Some(r"sdf+sdsfsd.as.sdsd") ); assert_eq!(extract_login(r"More@Than@One@at.com"), None); assert_eq!(extract_login(r"Not an email@email"), None); }