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我开始学习Rust，在Sushing中，我有hashmap3练习，编码如下

fn build_scores_table(results: String) -> HashMap<String, Team> {
    // The name of the team is the key and its associated struct is the value.
    let mut scores: HashMap<String, Team> = HashMap::new();

    for r in results.lines() {
        let v: Vec<&str> = r.split(',').collect();
        let team_1_name = v[0].to_string();
        let team_1_score: u8 = v[2].parse().unwrap();
        let team_2_name = v[1].to_string();
        let team_2_score: u8 = v[3].parse().unwrap();
        let t1 = scores.entry(team_1_name.clone()).or_insert(Team {
            name: team_1_name,
            goals_scored: 0,
            goals_conceded: 0,
        });
        t1.goals_scored += team_1_score;
        t1.goals_conceded += team_2_score;

        let t2 = scores.entry(team_2_name.clone()).or_insert(Team {
            name: team_2_name,
            goals_scored: 0,
            goals_conceded: 0,
        });
        t2.goals_conceded += team_1_score;
        t2.goals_scored += team_2_score;
        // TODO: Populate the scores table with details extracted from the
        // current line. Keep in mind that goals scored by team_1
        // will be the number of goals conceded from team_2, and similarly
        // goals scored by team_2 will be the number of goals conceded by
        // team_1.
    }
    println!("{:?}", scores);

    scores
}

但随后也找到了GitHub中其他铁 rust 开发和使用的答案

let t1 = scores.entry(team_1_name.clone()).or_insert(Team {
        name: team_1_name,
        goals_scored: 0,
        goals_conceded: 0,
    });
    (*t1).goals_scored += team_1_score;
    (*t1).goals_conceded += team_2_score;

    let t2 = scores.entry(team_2_name.clone()).or_insert(Team {
        name: team_2_name,
        goals_scored: 0,
        goals_conceded: 0,
    });
    (*t2).goals_conceded += team_1_score;
    (*t2).goals_scored += team_2_score;

这两个实现都能工作，并且通过了练习测试，但是在这里使用(*t1)有什么意义呢？抱歉问了这个愚蠢的问题，感谢您的帮助。