10HashMap

最新推荐文章于 2025-12-10 21:59:34 发布

原创最新推荐文章于 2025-12-10 21:59:34 发布 · 106 阅读

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文章通过示例展示了在Rust语言中使用HashMap时，由于String类型不实现CopyTrait，导致值移动后不能再次借用的问题。通过修改为借用引用的方式解决了这一问题。

use std::collections::HashMap; fn main() { let teams = vec![String::from("Blue"), String::from("Yellow")]; let initial_score = vec![10, 20]; let scores: HashMap<_, _> = teams.iter().zip(initial_score.iter()).collect(); println!("{:?}", scores); }

use std::collections::HashMap; fn main() { let f_name = String::from("a"); let f_value = String::from("b"); let mut map = HashMap::new(); map.insert(f_name, f_value); // println!("{} {}", f_name, f_value);//打开执行会报错 } error[E0382]: borrow of moved value: `f_name` --> src/main.rs:8:23 | 4 | let f_name = String::from("a"); | ------ move occurs because `f_name` has type `String`, which does not implement the `Copy` trait ... 7 | map.insert(f_name, f_value); | ------ value moved here 8 | println!("{} {}", f_name, f_value); | ^^^^^^ value borrowed here after move |

而对于实现了Copy Trait的使用如下，就不会报错

use std::collections::HashMap; fn main() { let f_name = "a"; let f_value = "b"; let mut map = HashMap::new(); map.insert(f_name, f_value); println!("{} {}", f_name, f_value);//打开执行会报错 }

use std::collections::HashMap; fn main() { let f_name = String::from("a"); let f_value = String::from("b"); let mut map = HashMap::new(); map.insert(&f_name, &f_value); println!("{} {}", f_name, f_value);//打开执行不会报错 } OK