【Rust】可选枚举（三）

环境

• Time 2022-03-25
• Rust 1.59.0

示例

iter_mut

fn main() {
    let mut name = Some("JiangBo".to_owned());
    println!("{:?}", name.iter_mut().next());
}

and

fn main() {
    let name = Some("JiangBo");
    println!("{:?}", name.and(Some("Rust")));
}

and_then

fn main() {
    let name = Some("JiangBo");
    println!("{:?}", name.and_then(|e| Some(e.len())));
}

filter

fn main() {
    let name = Some("JiangBo");
    println!("{:?}", name.filter(|e| e.is_empty()));
}

or

fn main() {
    let name = Some("JiangBo");
    println!("{:?}", name.or(None));
}

or_else

fn main() {
    let name = Some("JiangBo");
    println!("{:?}", name.or_else(|| None));
}

xor

fn main() {
    let name = Some("JiangBo");
    println!("{:?}", name.xor(None));
}

insert

fn main() {
    let mut name = Some("JiangBo");
    println!("{:?}", name.insert("Rust"));
}

get_or_insert

fn main() {
    let mut name = Some("JiangBo");
    println!("{:?}", name.get_or_insert("Rust"));
}

总结

了解了可选枚举中相关的一些方法。

附录