【Rust】哈希映射（二）

环境

• Time 2022-03-24
• Rust 1.59.0

示例

into_values

fn main() {
    let map = HashMap::from([("a", 1), ("b", 2), ("c", 3)]);
    map.into_values().for_each(|e| println!("{e:?}"));
}

iter

fn main() {
    let map = HashMap::from([("a", 1), ("b", 2), ("c", 3)]);
    map.iter().for_each(|e| println!("{e:?}"));
}

iter_mut

fn main() {
    let mut map = HashMap::from([("a", 1), ("b", 2), ("c", 3)]);
    map.iter_mut().for_each(|e| println!("{e:?}"));
}

into_iter

fn main() {
    let map = HashMap::from([("a", 1), ("b", 2), ("c", 3)]);
    map.into_iter().for_each(|e| println!("{e:?}"));
}

len

fn main() {
    let map = HashMap::from([("a", 1), ("b", 2), ("c", 3)]);
    println!("{:?}", map.len());
}

is_empty

fn main() {
    let map = HashMap::from([("a", 1), ("b", 2), ("c", 3)]);
    println!("{:?}", map.is_empty());
}

drain

fn main() {
    let mut map = HashMap::from([("a", 1), ("b", 2), ("c", 3)]);
    map.drain().for_each(|e| println!("{e:?}"));
}

retain

fn main() {
    let mut map = HashMap::from([("a", 1), ("b", 2), ("c", 3)]);
    map.retain(|_, v| *v % 2 == 0);
    println!("{map:?}");
}

clear

fn main() {
    let mut map = HashMap::from([("a", 1), ("b", 2), ("c", 3)]);
    map.clear();
    println!("{map:?}");
}

总结

了解了哈希映射中相关的一些方法。

附录