【Rust】结果枚举（一）
环境
- Time 2022-03-24
- Rust 1.59.0
示例
is_ok
fn main() {
let result: Result<i32, &str> = Ok(44);
println!("{:?}", result.is_ok());
}
is_err
fn main() {
let result: Result<i32, &str> = Ok(44);
println!("{:?}", result.is_err());
}
ok
fn main() {
let result: Result<i32, &str> = Ok(44);
println!("{:?}", result.ok());
}
err
fn main() {
let result: Result<i32, &str> = Ok(44);
println!("{:?}", result.err());
}
as_ref
fn main() {
let result: Result<i32, &str> = Ok(44);
println!("{:?}", result.as_ref());
}
map
fn main() {
let result: Result<i32, &str> = Ok(44);
println!("{:?}", result.map(|e| e / 4));
}
map_or
fn main() {
let result: Result<i32, &str> = Ok(44);
println!("{:?}", result.map_or(22, |e| e / 4));
}
map_or_else
fn main() {
let result: Result<i32, &str> = Ok(44);
println!("{:?}", result.map_or_else(|_| 2, |e| e / 4));
}
map_err
fn main() {
let result: Result<i32, &str> = Err("error");
println!("{:?}", result.map_err(|e| format!("[{}]", e)));
}
总结
了解了结果枚举中相关的一些方法。
