pub fn arrange_phrase(phrase: &str) -> String {

    // split phrase by whitespace

    let split = phrase.split_whitespace();

​

    // create a "pairs" data structure which is a vector of Strings.

    let mut pairs: Vec<(i32, String)> = vec![];

​

    // loop over split words to build the pairs list.

    for word in split {

        // loop over the word and extract the numeric string, using it as a "key" to the tupele in the tuple list.

        for ch in word.chars() {

            if ch.is_numeric() {

                let num = ch.to_string().parse::<i32>().unwrap();

                let new_word = word.replace(ch, "");

                pairs.push((num, new_word));

                break;

            }

        }

    }

​

    pairs.sort();

​

    let mut result: String = String::new();

​

    for tup in pairs {

        result.push_str(&tup.1);

        result.push(' ')

    }

    result = result.trim().to_string();

​

    result

}