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无法访问循环中向量的元素

rust

0

Sumchans · 技术社区 · 6 年前

我想通过println打印向量的元素!在一个循环中。

error[E0277]: the type `[i32]` cannot be indexed by `i32`
   |
21 |         s = v[outercount];
   |             ^^^^^^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
   |
   = help: the trait `std::slice::SliceIndex<[i32]>` is not implemented for `i32`
   = note: required because of the requirements on the impl of `std::ops::Index<i32>` for `std::vec::Vec<i32>`

let v = vec![1,4,2,4,1,8];
let mut outercount:i32 = 0;
loop {
    outercount += 1;
    s = v[outercount];
    println!("{}", s);
    if outercount == (v.len() - 1) as i32 { break; }
}

0 回复 | 直到 6 年前

1

2

akuiper 6 年前

如错误消息所示,索引需要 usize i32 :

let v = vec![1,4,2,4,1,8];
let mut outercount: usize = 0;    // declare outercount as usize instead of i32
loop {
    let s = v[outercount];        // need to declare variable here
    println!("{}", s);
    outercount += 1;
    if outercount == v.len() { break; }
}

2

3

matiu 6 年前

我知道这可能对你的代码@Sumchans没有帮助,但我不得不写一个 more idiomatic 版本。我希望它能帮助某些人:

fn main() {
   let v = vec![1,4,2,4,1,8];
   v.iter().for_each(|n| println!("{}", n));
}

3

1

Taimoor 6 年前

fn main(){
let v = vec![1,3,5,7,9]; 
for i in v.iter(){ //also for i in &v 
  println!("{:?}",i);
 }
}

你也可以用

let outercount = v[0]; //rust will automatically infer this as [i32]