// 需要使用 cargo test 来运行测例
#[test]
fn test(){
assert_eq!(2, 2);
}
// 完整测例
#[cfg(test)]
mod tests{
use super::*;
#[test]
fn one_test(){
assert_eq!(1, 3);
}
...
#[test]
#[should_painic] // 崩溃点
fn panics_not_right(){
println("");
}
// 到达should_painic就崩溃，测试完成
}
- 在Cargo.toml中有[dependencies]标签
[package]
name = "demo_rust"
version = "0.0.0"
authors = ["wang"]
ediion = "2022"
[dependencies]
rand = "0.7.3"
// 代码使用
use rand;
let random_u16 = rand::random::<u16>();
println!("{}", random_u16);
// rand的另一种使用
use rand::{thread_rng, Rng};
let mut number_maker = thread_rng();
//随机生成1到11之间的数字
println!("{}", number_maker.gen_range(1, 11));
- .iter(), .iter_mut(), into_iter()在rayon中是这样写的:
- .par_iter(), .par_iter_mut(), par_into_iter(). 所以你只要加上par_，你的代码就会变得快很多。(par的意思是 "并行")
use rayon::prelude::*; // Import rayon
// .enumerate()来获取每个数字的索引
// .par_iter_mut() 来遍历
fn main() {
let mut my_vec = vec![0; 200_000];
my_vec.par_iter_mut().enumerate().for_each(|(index, number)| *number+=index+1); // add par_ to iter_mut
println!("{:?}", &my_vec[5000..5005]);
}
// Serialize, Deserialize
#[derive(Serialize, Deserialize, Debug)]
struct Point {
x: i32,
y: i32,
}
- 不能使用for，可使用.iter()和&来切片
- 解构
let my_city = ["WeiFang", "BeiJing"];
for city in &my_city{
}
for city in my_city.iter(
)
- 可用.escape_unicode() 获取Unicode号码
- char::from(99) 或者char::try_from().unwarp_or('-')
- 不会崩溃 .checked_add(), .checked_sub(), .checked_mul(), .checked_div()
- 实现Add
use std::ops::Add; // first bring in Add
#[derive(Debug, Copy, Clone, PartialEq)] // PartialEq is probably the most important part here. You want to be able to compare numbers
struct Point {
x: i32,
y: i32,
}
impl Add for Point {
// 相加的时候另一个的数值
type Output = Self; // Remember, this is called an "associated type": a "type that goes together".
// In this case it's just another Point
fn add(self, other: Self) -> Self {
Self {
x: self.x + other.x,
y: self.y + other.y,
}
}
}
let p1 = Point{1, 2};
let p2 = Point{1, 2};
p1+p2 就调用了Add
- Sub Mul Div 基本一样，+=、-=、*=和/=，只要加上Assign:AddAssign、SubAssign、MulAssign和DivAssign即可
- % 被称为 Rem, - 被称为 Neg
- f32和f64
- .floor(): 给你下一个最低的整数.
- .ceil(): 给你下一个最高的整数。
- .round(): 如果小数部分大于等于0.5，返回数值加1;如果小数部分小于0.5，返回相同数值。这就是所谓的四舍五入，因为它给你一个 "舍入"的数字(一个数字的简短形式)。
- .trunc():只是把小数点号后的部分截掉。Truncate是 "截断"的意思。
- .fold(): 用来得到最高或者最低的数
let my_vec = vec![8.0_f64, 7.6, 9.4, 10.0, 22.0, 77.345, 10.22, 3.2, -7.77, -10.0];
let maximum = my_vec.iter().fold(f64::MIN, |current_number, next_number| current_number.max(*next_number)); // Note: start with the lowest possible number for an f64.
let minimum = my_vec.iter().fold(f64::MAX, |current_number, next_number| current_number.min(*next_number)); // And here start with the highest possible number
println!("{}, {}", maximum, minimum);
let true_false = (true, false);
println!("{} {}", true_false.0 as u8, true_false.1 as i32);
let (tru, fals) = (true.then(|| 8), false.then(|| 8));
println!("{:?}, {:?}", tru, fals);
- sort() 升序排列，最小的在前
- sort_unstable() 更快速的排序
- dedup() 去重
- .push() 加入一个char
- .push_str() 加入一个&str
- std::ffi 外部函数接口
- OsString 非unicode
- std::mem
- .size_of() .size_of_val()和.drop()
use std::mem;
fn main() {
println!("{}", mem::size_of::<i32>());
let my_array = [8; 50];
println!("{}", mem::size_of_val(&my_array));
let mut some_string = String::from("You can drop a String because it's on the heap");
mem::drop(some_string);
// some_string.clear(); If we did this it would panic
}
打印结果
4
200
mem::swap(&mut T, &mut T)
pub fn replace<T>(dest: &mut T, mut src: T) -> T {
swap(dest, &mut src);
src
}
let mut number_vec = vec![8, 7, 0, 2, 49, 9999];
let mut new_vec = vec![];
number_vec.iter_mut().for_each(|number| {
let taker = mem::take(number);
new_vec.push(taker);
});
- Instant::now()获得系统时间
- 与sleep联合使用
use std::time::Duration;
use std::thread::sleep;
fn main() {
let three_seconds = Duration::from_secs(3);
println!("I must sleep now.");
sleep(three_seconds);
println!("Did I miss anything?");
}
- column!() 当前列数
- file!() 文件的名称
- line!() 当前行
- module_path!() 当前模块名称。
- 使用macro_rules!{}
- 接受一个输入然后给一个输出
macro_rules! give_six{
(6)=>{6};
()=>{println!("None")}
}
let six = give_size(6); //返回6
give_size(); // 打印 None
// 2. 改进
// $input:expr 对于一个表达式，给他起一个变量名$input
/*
expr还可替换：
item: an Item
block: a BlockExpression
stmt: a Statement without the trailing semicolon (except for item statements that require semicolons)
pat: a Pattern
expr: an Expression
ty: a Type
ident: 标识符 an IDENTIFIER_OR_KEYWORD
path: a TypePath style path
tt: 表示树 a TokenTree (a single token or tokens in matching delimiters (), [], or {})
meta: an Attr, the contents of an attribute
lifetime: a LIFETIME_TOKEN
vis: a possibly empty Visibility qualifier
literal: matches -?LiteralExpression
*/
macro_rules! might_print{
($input:expr)=>{
println!("{}", $input)
}
}
- cargo run 建立并运行
- cargo build 构建程序
- cargo build --release 和 cargo run --release 发布模式
- cargo check 检查代码
- cargo new 项目名 新建项目
- cargo clean 清除
- cargo doc 创建
use std::io;
fn main(){
let mut input_string = String::new();
io::stdIn().read_line(&mut input_string).unwarp();
println!("{}", input_string);
}
use std::env::args;
fn main() {
let input = args();
for entry in input {
println!("You entered: {}", entry);
}
}
// 当运行cargo run ****时，****作为参数可以通过args()获得
for item in std::env::vars() {
println!("{:?}", item);
}
// 获得单个变量
env!("USER")
option_env!("ROOT").unwrap_or("Can't find ROOT"))
use std::fs;
use std::io::Write;
fn main() -> std::io::Result<()> {
fs::File::create("myfilename.txt")?.write_all(b"Let's put this in the file")?;
Ok(())
}
use std::fs;
use std::fs::OpenOptions;
use std::io::Write;
fn main() -> std::io::Result<()> {
fs::write(文件名, 内容);
let mut calvin_file = OpenOptions::new()
.append(true).read(true).open(文件名)?;
calvin_file.write_all(内容)?;
write!(&mut calvin_file, 内容)?;
fs::read_to_string(文件名)?;
Ok(())
}