Rust 备忘清单

查看: Rust 类型

// 打印输出
print!("Hello World\n");
// 打印后追加新行
println!("追加新行");
// 打印为错误
eprint!("这是一个错误\n");
// 打印为新行错误
eprintln!("这是新行的错误");

// 初始化和声明变量
let some_variable = "This_is_a_variable";
// 使变量可变
let mut mutable_variable = "Mutable";
// 分配多个变量
let (name, age) = ("ElementalX", 20);
// （全局）常量
const SCREAMING_SNAKE_CASE:i64 = 9;

// 行注释
/*.............块注释 */
/// 外部文档注释
//! 内部文档评论

另见: 注释 (doc.rust-lang.org)

fn test(){
  println!("这是一个函数!");
}
fn main(){
  test();
}

查看: Functions

macro_rules! foo {
  ($l:tt) => { bar!($l); }
}
macro_rules! bar {
  (3) => {}
}
foo!(3);

type Point = (u8, u8);
let p: Point = (41, 68);

let mut a: u32 = 8;
let b = 877_u64;
let c = 8999i64;
let d = -90;

let mut sixty_bit_float: f64 = 89.90;
let thirty_two_bit_float: f32 = 7.90;
let just_a_float = 69.69;

let true_val: bool = true;
let false_val: bool = false;
let just_a_bool = true;
let is_true = 8 < 5;  // => false

let first_letter_of_alphabet = 'a';
let explicit_char: char = 'F';
let implicit_char = '8';
let emoji = "\u{1f600}";   // => 😀

let community_name = "AXIAL";
let no_of_members: &str = "ten";
println!("社区的名称是 {community_name}，它有 {no_of_members} 个成员");

查看: 字符串

let mut array: [ i64; 4] = [1,2,3,4];
// 下限包括在内，上限不包括在内
let mut slices: &[i64] = &array[0..3]
println!("切片的元素是：{slices:?}");

let tuple = (1, 'A' , "Cool", 78, true);

let cs:&str = "备忘清单";
// => 为开发者分享备忘单
println!("为开发者分享 {cs}");

// 创建一个空字符串对象
let my_string = String::new;
// 转换为字符串对象
let S_string = a_string.to_string()
// 创建一个初始化的字符串对象
let lang = String::from("Rust");  
println!("First language is {lang}");

let rand = String::from("Random String");
rand.capacity()  // => 13

以字节为单位计算字符串的容量

let s = String::with_capacity(10);

指定一个足够大的容量值,来减少内存拷贝

let name = String::from("ElementalX");
name.contains("Element") // => true

检查子字符串是否包含在原始字符串中

let mut half_text = String::from("Hal");
half_text.push('f');    // => Half

let mut hi = String::from("Hey there...");
hi.push_str("How are you doing??");
// => Hey there...How are you doing??
println!("{hi}");

let str1 = r#"\hello"#;
println!("{}", str1);
// \hello

原生字符串，无需增加转义字符（\）转义

let str2 = b'a';
println!("{}", str2);
// 97
let str3 = b"\\hello";
println!("{:?}", str3);
// [92, 104, 101, 108, 108, 111]
let str4 = br#"\hello"#;
println!("{:?}", str4);
// [92, 104, 101, 108, 108, 111]

let v: Vec<i32> = Vec::new();
// 使用宏
let v1 = vec![1, 2, 3];

let v = vec![1, 2, 3, 4, 5];

let element = &v[100];
// panic，越界
let element2 = v.get(100);
println!("{:?}", element2);
//None

1. 只读取数组中的元素

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

2. 遍历的同时修改数组中的元素

   let mut v = vec![1, 2, 3];
   for i in &mut v {
       *i += 10
   }
   

     j0   j1   j2   j3   j4   j5
   ┌────┬────┬────┬────┬────┬────┐
i0 | 1  | 2  | 3  | 4  | 5  | 6  |
   ├────┼────┼────┼────┼────┼────┤
i1 | 6  | 5  | 4  | 3  | 2  | 1  |
   └────┴────┴────┴────┴────┴────┘

let arr = vec![
    vec![1, 2, 3, 4, 5, 6],
    vec![6, 5, 4, 3, 2, 1]
];

use std::collections::Ha