leetcode/source/valid_number/mod.rs

pub fn is_number(string: String) -> bool {
  let string = string.to_lowercase();

  if string.contains("inf") || string.contains("nan") {
    return false;
  }

  let mut parts = string.split('e');

  let valid_significand = match parts.next() {
    Some(part) => part.parse::<f64>().is_ok(),
    None => unreachable!(),
  };

  let valid_exponent = match parts.next() {
    Some(part) => part.parse::<isize>().is_ok(),
    None => true,
  };

  let nothing_remaining = parts.next().is_none();

  valid_significand && valid_exponent && nothing_remaining
}