如何从一个切片创建两个新的可变切片? [英] How do I create two new mutable slices from one slice?
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问题描述
我想获取一个可变切片并将内容复制到两个新的可变切片中.每个切片都是原始切片的一半.
I would like to take a mutable slice and copy the contents into two new mutable slices. Each slice being one half of the original.
我的尝试 #1:
let my_list: &mut [u8] = &mut [0, 1, 2, 3, 4, 5];
let list_a: &mut [u8] = my_list[0..3].clone();
let list_b: &mut [u8] = my_list[3..6].clone();
println!("{:?}", my_list);
println!("{:?}", list_a);
println!("{:?}", list_b);
输出:
error: no method named `clone` found for type `[u8]` in the current scope
--> src/main.rs:3:43
|
3 | let list_a: &mut [u8] = my_list[0..3].clone();
| ^^^^^
error: no method named `clone` found for type `[u8]` in the current scope
--> src/main.rs:4:43
|
4 | let list_b: &mut [u8] = my_list[3..6].clone();
| ^^^^^
我的尝试 #2:
let my_list: &mut [u8] = &mut [0, 1, 2, 3, 4, 5];
let list_a: &mut [u8] = my_list[0..3].to_owned();
let list_b: &mut [u8] = my_list[3..6].to_owned();
println!("{:?}", my_list);
println!("{:?}", list_a);
println!("{:?}", list_b);
输出:
error[E0308]: mismatched types
--> src/main.rs:12:29
|
12 | let list_a: &mut [u8] = my_list[0..3].to_owned();
| ^^^^^^^^^^^^^^^^^^^^^^^^ expected &mut [u8], found struct `std::vec::Vec`
|
= note: expected type `&mut [u8]`
found type `std::vec::Vec<u8>`
= help: try with `&mut my_list[0..3].to_owned()`
error[E0308]: mismatched types
--> src/main.rs:13:29
|
13 | let list_b: &mut [u8] = my_list[3..6].to_owned();
| ^^^^^^^^^^^^^^^^^^^^^^^^ expected &mut [u8], found struct `std::vec::Vec`
|
= note: expected type `&mut [u8]`
found type `std::vec::Vec<u8>`
= help: try with `&mut my_list[3..6].to_owned()`
我可以使用两个 Vec
并且只是循环输入并推送我猜的克隆值,但我希望有更好的方法来做到这一点:
I can use two Vec<u8>
and just loop over the input and push cloned values I guess, but I was hoping there was a nicer way to do this:
extern crate rand;
use rand::{thread_rng, Rng};
fn main() {
let my_list: &mut [u8] = &mut [0; 100];
thread_rng().fill_bytes(my_list);
let list_a = &mut Vec::new();
let list_b = &mut Vec::new();
for i in 0..my_list.len() {
if i < my_list.len() / 2 {
list_a.push(my_list[i].clone());
} else {
list_b.push(my_list[i].clone());
}
}
println!("{:?}", list_a.as_slice());
println!("{:?}", list_b.as_slice());
println!("{:?}", my_list);
}
推荐答案
您可以通过使用多种方法克隆元素来直接从切片构建向量:
You can build vectors from slices directly by cloning the elements using multiple methods:
fn main() {
let my_list: &mut [u8] = &mut [0, 1, 2, 3, 4, 5];
let mut vec1 = my_list[0..2].to_vec();
let mut vec2: Vec<u8> = my_list[2..4].into();
let mut vec3 = my_list[2..6].to_owned();
println!("{:?}", vec1);
println!("{:?}", vec2);
}
你最初的问题是因为所有这些都返回一个 Vec
但你试图声称它是一个切片,相当于:
Your original problem was caused because all of these return a Vec
but you were attempting to claim that it was a slice, equivalent to:
let thing: &mut [u8] = Vec::new();
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