Rust使用HashMap统计出现次数

代码如下：

use std::collections::HashMap;

fn main() {
    let text = "Hello world good world";

    let mut map = HashMap::new();
    for word in text.split_whitespace() {
        let count = map.entry(word).or_insert(0);
        *count += 1;
    }

    println!("{:#?}", map);
}

输出结果：

{
    "Hello": 1,
    "good": 1,
    "world": 2,
}