Rust语言之集合

---

Rust官方文档

针对集合Rust提供了两种复合数据类型，元组和数组。

一、元组（tuple）

元组（tuple）是一种复合数据类型，可以包含不同类型的元素，但一旦定义，元组长度不可变的。

1.元组定义

# 标准定义
fn main() {
    let tup: (i32, f64, u8, &str) = (500, 6.4, 1, "hello");
}
# 也可省略类型
fn main() {
    let tup= (500, 6.4, 1, "hello");
}

2.元组使用

Rust中使用元组数据有两种方法。

• 解构 即将一个元组拆成多个部分，每个部分赋值给一个变量
• 索引 即使用’.'配合索引进行使用

解构

fn main() {
    let tup: (i32, f64, u8, &str) = (500, 6.4, 1, "hello");
    let (a,b,c,d) = tup;
    println!("a={0},b={1},c={2},d={3}",a,b,c,d);
}
$cargo run hello
   Compiling hello v0.1.0 (/home/kali/Desktop/ctf/script/RustPro/hello)
    Finished dev [unoptimized + debuginfo] target(s) in 0.34s
     Running `target/debug/hello hello`
a=500,b=6.4,c=1,d=hello

索引

fn main() {
    let tup: (i32, f64, u8, &str) = (500, 6.4, 1, "hello");
    println!("a={0},b={1},c={2},d={3}",tup.0,tup.1,tup.2,tup.3);
}
$argo run hello
   Compiling hello v0.1.0 (/home/kali/Desktop/ctf/script/RustPro/hello)
    Finished dev [unoptimized + debuginfo] target(s) in 0.31s
     Running `target/debug/hello hello`
a=500,b=6.4,c=1,d=hello

3.元组修改

理论上元组是不能进行修改的，但是如果定义为可变元组，则可以修改元组内容，但修改值的类型必须和定义时一致。

特别注意：元组长度始终无法修改

非可变元组

fn main() {
    let  tup: (i32, f64, u8, &str) = (500, 6.4, 1, "hello");
    println!("value:{}",tup.0);
    tup.0 = 1000;
    println!("After:{}",tup.0);
}

$cargo run hello
   Compiling hello v0.1.0 (/home/kali/Desktop/ctf/script/RustPro/hello)
error[E0594]: cannot assign to `tup.0`, as `tup` is not declared as mutable
 --> src/main.rs:4:5
  |
4 |     tup.0 = 1000;
  |     ^^^^^^^^^^^^ cannot assign
  |
help: consider changing this to be mutable
  |
2 |     let  mut tup: (i32, f64, u8, &str) = (500, 6.4, 1, "hello");
  |          +++

For more information about this error, try `rustc --explain E0594`.
error: could not compile `hello` (bin "hello") due to previous error

可变元组

fn main() {
    let mut tup: (i32, f64, u8, &str) = (500, 6.4, 1, "hello");
    println!("value:{}",tup.0);
    tup.0 = 1000;
    println!("After:{}",tup.0);
}
$cargo run hello
   Compiling hello v0.1.0 (/home/kali/Desktop/ctf/script/RustPro/hello)
    Finished dev [unoptimized + debuginfo] target(s) in 0.22s
     Running `target/debug/hello hello`
value:500
After:1000

类型不一致

fn main() {
    let mut tup: (i32, f64, u8, &str) = (500, 6.4, 1, "hello");
    println!("value:{}",tup.0);
    tup.0 = "what?";
    println!("After:{}",tup.0);
}
$cargo run hello
   Compiling hello v0.1.0 (/home/kali/Desktop/ctf/script/RustPro/hello)
error[E0308]: mismatched types
 --> src/main.rs:4:13
  |
4 |     tup.0 = "what?";
  |     -----   ^^^^^^^ expected `i32`, found `&str`
  |     |
  |     expected due to the type of this binding

For more information about this error, try `rustc --explain E0308`.
error: could not compile `hello` (bin "hello") due to previous error

二、数组

目前据我所知，Rust中可以称为数组的有可变数组、不可变数组和向量.

• 数组只能是单一数据类型的合集，比元组多了遍历的功能
• 向量与数组一样，是单一数据类型的合计，但是比数组强大太多，具有增、删、插入、排序等操作

1.数组

不可变数组定义

# 标准定义方法
fn main() {
    let a: [i32; 5] = [1, 2, 3, 4, 5];
}

=> a =[1, 2, 3, 4, 5]
# 简化类型定义方法
fn main() {
    let a = [1, 2, 3, 4, 5];
}

=> a =[1, 2, 3, 4, 5]
# 相同初始值定义方法
fn main() {
    let a = [3; 5];
}

=> a =[3, 3, 3, 3, 3]

可变数组定义

定义方法与不可变数组一致，只是加了mut关键字

fn main() {
    let mut v: [i32; 5] = [3;5];
}

=> a =[3, 3, 3, 3, 3]

数组使用

可以利用数组名[下标]的方式对数组内容进行使用，数组内下标从0计算。

fn main() {  
    let array = [1, 2, 3, 4, 5];  
    println!("Second value:{:?}", array[1]);  
}

$cargo run hello
   Compiling hello v0.1.0 (/home/kali/Desktop/ctf/script/RustPro/hello)
    Finished dev [unoptimized + debuginfo] target(s) in 0.24s
     Running `target/debug/hello hello`
Second value:2

数组修改

fn main() {  
    let mut array = [1, 2, 3, 4, 5];  
    println!("value :{:?}", array);  
    array[2] = 100;
    println!("After :{:?}", array);  
}

$cargo run hello
   Compiling hello v0.1.0 (/home/kali/Desktop/ctf/script/RustPro/hello)
    Finished dev [unoptimized + debuginfo] target(s) in 0.22s
     Running `target/debug/hello hello`
value :[1, 2, 3, 4, 5]
After :[1, 2, 100, 4, 5]

数组的遍历

# 值遍历
fn main() {  
    let array = [1, 2, 3, 4, 5];  
    for i in array{
        println!("{}",i);
    }
}

$cargo run hello
   Compiling hello v0.1.0 (/home/kali/Desktop/ctf/script/RustPro/hello)
    Finished dev [unoptimized + debuginfo] target(s) in 0.24s
     Running `target/debug/hello hello`
1
2
3
4
5

# 下标遍历
fn main() {  
    let array = [1, 2, 3, 4, 5];  
    for i in 0..5{
        println!("{}",array[i]);
    }
}

$cargo run hello
   Compiling hello v0.1.0 (/home/kali/Desktop/ctf/script/RustPro/hello)
    Finished dev [unoptimized + debuginfo] target(s) in 0.21s
     Running `target/debug/hello hello`
1
2
3
4
5

2.动态数组-向量（Vector）

Rust中的向量（Vector）是一种动态数组，它可以存储相同类型的元素，并且其大小可以在运行时增长或缩小。

向量定义

let mut v1 = Vec::new(); // 创建一个空的向量  
let v2 = vec![1, 2, 3]; // 创建一个包含初始元素的向量

向量遍历

fn main() {  
    let v = vec![1, 2, 3];  
    for i in &v {  
        println!("{}", i);  
    }
}

向量追加

 fn main() {  
    let mut v = Vec::new();
    v.push(1);
    v.push(2);
    v.push(3);
    println!("{:?}",v);
}

$cargo run hello
    Finished dev [unoptimized + debuginfo] target(s) in 0.00s
     Running `target/debug/hello hello`
[1, 2, 3]

向量插入

fn main() {  
    let mut vec = vec![1, 2, 4, 5];  
    vec.insert(2, 3); // 在索引2的位置插入元素3  
    println!("{:?}", vec);
}

$cargo run hello
   Compiling hello v0.1.0 (/home/kali/Desktop/ctf/script/RustPro/hello)
    Finished dev [unoptimized + debuginfo] target(s) in 0.26s
     Running `target/debug/hello hello`
[1, 2, 3, 4, 5]

向量删除

remove方法

fn main() {  
    let mut vec = vec![1, 2, 3, 4, 5];  
    let removed_element = vec.remove(2); // 删除索引2处的元素  
    println!("Removed element: {}", removed_element); // 输出: Removed element: 3  
    println!("{:?}", vec); // 输出: [1, 2, 4, 5]
}

pop方法-删除最好一个元素

fn main() {  
    let mut vec = vec![1, 2, 3];
    vec.pop();
    println!("{:?}", vec); // 输出: [1, 2]
}

truncate方法-缩减向量

fn main() {  
    let mut vec = vec![1, 2, 3, 4, 5];  
    vec.truncate(3); // 缩减向量的大小为3  
    println!("{:?}", vec); // 输出: [1, 2, 3]
}

clear方法-清空向量

fn main() {  
    let mut vec = vec![1, 2, 3, 4, 5];  
    vec.clear(); // 删除所有元素  
    println!("{:?}", vec); // 输出: []
}

drain方法-删除范围内向量

fn main() {  
    let mut vec = vec![1, 2, 3, 4, 5];  
    let drained: Vec<_> = vec.drain(1..3).collect(); // 删除索引1到2的元素（不包括3）并收集它们  
    println!("Drained elements: {:?}", drained); // 输出: Drained elements: [2, 3]  
    println!("{:?}", vec); // 输出: [1, 4, 5]
}

向量排序

sort方法

fn main() {  
    let mut numbers = vec![5, 2, 9, 1, 5, 6];  
    numbers.sort();  
    println!("{:?}", numbers); // 输出: [1, 2, 5, 5, 6, 9]
}

sort_by方法

# 升序
fn main() {  
    let mut numbers = vec![5, 2, 9, 1, 5, 6];  
    numbers.sort_by(|a, b| a.cmp(b));  
    println!("{:?}", numbers); // 输出: [1, 2, 5, 5, 6, 9]
}
# 降序
fn main() {  
    let mut numbers = vec![5, 2, 9, 1, 5, 6];  
    numbers.sort_by(|a, b| b.cmp(a));  
    println!("{:?}", numbers); // 输出: [9, 6, 5, 5, 2, 1]
}

逆转向量

fn main() {  
    let mut numbers = vec![1, 2, 3, 4, 5];  
    numbers.reverse();  
    println!("{:?}", numbers); // 输出: [5, 4, 3, 2, 1]
}