mirror of https://github.com/sunface/rust-course
Rustln
3 years ago
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GitHub
commit
a21e10a2a3
@ -1,4 +0,0 @@
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# 实用算法
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本章将收集一些在实战中经常使用的算法 API。
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> Note: 这里没有具体的算法实现，都是关于如何应用的
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@ -1,155 +0,0 @@
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# 生成随机值
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### 生成随机数
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使用 [rand::thread_rng](https://docs.rs/rand/*/rand/fn.thread_rng.html) 可以获取一个随机数生成器 [rand::Rng](https://docs.rs/rand/0.8.5/rand/trait.Rng.html) ，该生成器需要在每个线程都初始化一个。
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整数的随机分布范围等于类型的取值范围，但是浮点数只分布在 `[0, 1)` 区间内。
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```rust,editable
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use rand::Rng;
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fn main() {
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let mut rng = rand::thread_rng();
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let n1: u8 = rng.gen();
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let n2: u16 = rng.gen();
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println!("Random u8: {}", n1);
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println!("Random u16: {}", n2);
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println!("Random u32: {}", rng.gen::<u32>());
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println!("Random i32: {}", rng.gen::<i32>());
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println!("Random float: {}", rng.gen::<f64>());
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}
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```
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### 指定范围生成随机数
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使用 [Rng::gen_range](https://rust-lang-nursery.github.io/rust-cookbook/algorithms/randomness.html) 生成 [0, 10) 区间内的随机数( 右开区间，不包括 `10` )。
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```rust,editable
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use rand::Rng;
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fn main() {
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let mut rng = rand::thread_rng();
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println!("Integer: {}", rng.gen_range(0..10));
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println!("Float: {}", rng.gen_range(0.0..10.0));
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}
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```
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[Uniform](https://docs.rs/rand/*/rand/distributions/uniform/struct.Uniform.html) 可以用于生成<ruby>均匀分布<rt>uniform distribution</rt></ruby>的随机数。当需要在同一个范围内重复生成随机数时，该方法虽然和之前的方法效果一样，但会更快一些。
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```rust,editable
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use rand::distributions::{Distribution, Uniform};
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fn main() {
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let mut rng = rand::thread_rng();
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let die = Uniform::from(1..7);
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loop {
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let throw = die.sample(&mut rng);
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println!("Roll the die: {}", throw);
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if throw == 6 {
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break;
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}
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}
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}
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```
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### 使用指定分布来生成随机数
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默认情况下，`rand` 包使用均匀分布来生成随机数，而 [rand_distr](https://docs.rs/rand_distr/*/rand_distr/index.html) 包提供了其它类型的分布方式。
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首先，你需要获取想要使用的分布的实例，然后在 [rand::Rng](https://docs.rs/rand/*/rand/trait.Rng.html) 的帮助下使用 [Distribution::sample](https://docs.rs/rand/*/rand/distributions/trait.Distribution.html#tymethod.sample) 对该实例进行取样。
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如果想要查询可用的分布列表，可以访问[这里](https://docs.rs/rand_distr/*/rand_distr/index.html)，下面的示例中我们将使用 [Normal](https://docs.rs/rand_distr/0.4.3/rand_distr/struct.Normal.html) 分布:
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```rust,editable
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use rand_distr::{Distribution, Normal, NormalError};
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use rand::thread_rng;
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fn main() -> Result<(), NormalError> {
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let mut rng = thread_rng();
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let normal = Normal::new(2.0, 3.0)?;
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let v = normal.sample(&mut rng);
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println!("{} is from a N(2, 9) distribution", v);
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Ok(())
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}
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```
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### 在自定义类型中生成随机值
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使用 [Distribution](https://docs.rs/rand/*/rand/distributions/trait.Distribution.html) 特征包裹我们的自定义类型，并为 [Standard](https://docs.rs/rand/*/rand/distributions/struct.Standard.html) 实现该特征，可以为自定义类型的指定字段生成随机数。
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```rust,editable
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use rand::Rng;
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use rand::distributions::{Distribution, Standard};
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#[derive(Debug)]
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struct Point {
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x: i32,
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y: i32,
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}
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impl Distribution<Point> for Standard {
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fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Point {
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let (rand_x, rand_y) = rng.gen();
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Point {
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x: rand_x,
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y: rand_y,
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}
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}
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}
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fn main() {
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let mut rng = rand::thread_rng();
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// 生成一个随机的 Point
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let rand_point: Point = rng.gen();
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println!("Random Point: {:?}", rand_point);
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// 通过类型暗示( hint )生成一个随机的元组
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let rand_tuple = rng.gen::<(i32, bool, f64)>();
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println!("Random tuple: {:?}", rand_tuple);
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}
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```
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### 生成随机的字符串(A-Z, a-z, 0-9)
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通过 [Alphanumeric](https://docs.rs/rand/0.8.5/rand/distributions/struct.Alphanumeric.html) 采样来生成随机的 ASCII 字符串，包含从 `A-Z, a-z, 0-9` 的字符。
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```rust,editble
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use rand::{thread_rng, Rng};
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use rand::distributions::Alphanumeric;
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fn main() {
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let rand_string: String = thread_rng()
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.sample_iter(&Alphanumeric)
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.take(30)
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.map(char::from)
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.collect();
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println!("{}", rand_string);
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}
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```
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### 生成随机的字符串( 用户指定 ASCII 字符 )
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通过 [gen_string](https://docs.rs/rand/0.8.5/rand/trait.Rng.html#method.gen_range) 生成随机的 ASCII 字符串，包含用户指定的字符。
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```rust,editable
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fn main() {
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use rand::Rng;
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const CHARSET: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZ\
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abcdefghijklmnopqrstuvwxyz\
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0123456789)(*&^%$#@!~";
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const PASSWORD_LEN: usize = 30;
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let mut rng = rand::thread_rng();
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let password: String = (0..PASSWORD_LEN)
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.map(|_| {
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let idx = rng.gen_range(0..CHARSET.len());
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CHARSET[idx] as char
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})
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.collect();
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println!("{:?}", password);
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}
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```
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@ -1,84 +0,0 @@
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## Vector 排序
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### 对整数 Vector 排序
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以下示例使用 [Vec::sort](https://doc.rust-lang.org/std/vec/struct.Vec.html#method.sort) 来排序，如果大家希望获得更高的性能，可以使用 [Vec::sort_unstable](https://doc.rust-lang.org/std/vec/struct.Vec.html#method.sort_unstable)，但是该方法无法保留相等元素的顺序。
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```rust,editable
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fn main() {
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let mut vec = vec![1, 5, 10, 2, 15];
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vec.sort();
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assert_eq!(vec, vec![1, 2, 5, 10, 15]);
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}
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```
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### 对浮点数 Vector 排序
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浮点数数组可以使用 [Vec::sort_by](https://doc.rust-lang.org/std/primitive.slice.html#method.sort_by) 和 [PartialOrd::partial_cmp](https://doc.rust-lang.org/std/cmp/trait.PartialOrd.html#tymethod.partial_cmp) 进行排序。
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```rust,editable
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fn main() {
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let mut vec = vec![1.1, 1.15, 5.5, 1.123, 2.0];
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vec.sort_by(|a, b| a.partial_cmp(b).unwrap());
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assert_eq!(vec, vec![1.1, 1.123, 1.15, 2.0, 5.5]);
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}
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```
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### 对结构体 Vector 排序
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以下示例中的结构体 `Person` 将实现基于字段 `name` 和 `age` 的自然排序。为了让 `Person` 变为可排序的，我们需要为其派生 `Eq、PartialEq、Ord、PartialOrd` 特征，关于这几个特征的详情，请见[这里](https://course.rs/advance/confonding/eq.html)。
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当然，还可以使用 [vec:sort_by](https://doc.rust-lang.org/std/vec/struct.Vec.html#method.sort_by) 方法配合一个自定义比较函数，只按照 `age` 的维度对 `Person` 数组排序。
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```rust,editable
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#[derive(Debug, Eq, Ord, PartialEq, PartialOrd)]
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struct Person {
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name: String,
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age: u32
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}
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impl Person {
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pub fn new(name: String, age: u32) -> Self {
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Person {
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name,
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age
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}
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}
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}
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fn main() {
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let mut people = vec![
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Person::new("Zoe".to_string(), 25),
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Person::new("Al".to_string(), 60),
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Person::new("John".to_string(), 1),
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];
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// 通过派生后的自然顺序(Name and age)排序
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people.sort();
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assert_eq!(
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people,
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vec![
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Person::new("Al".to_string(), 60),
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Person::new("John".to_string(), 1),
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Person::new("Zoe".to_string(), 25),
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]);
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// 只通过 age 排序
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people.sort_by(|a, b| b.age.cmp(&a.age));
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assert_eq!(
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people,
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vec![
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Person::new("Al".to_string(), 60),
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Person::new("Zoe".to_string(), 25),
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Person::new("John".to_string(), 1),
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]);
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}
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```
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@ -1,50 +0,0 @@
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# ANSI 终端
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[ansi_term](https://crates.io/crates/ansi_term) 包可以帮我们控制终端上的输出样式，例如使用颜色文字、控制输出格式等，当然，前提是在 ANSI 终端上。
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`ansi_term` 中有两个主要数据结构：[ANSIString](https://docs.rs/ansi_term/0.12.1/ansi_term/type.ANSIString.html) 和 [Style](https://docs.rs/ansi_term/0.12.1/ansi_term/struct.Style.html)。
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`Style` 用于控制样式：颜色、加粗、闪烁等，而前者是一个带有样式的字符串。
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## 颜色字体
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```rust,editable
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use ansi_term::Colour;
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fn main() {
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println!("This is {} in color, {} in color and {} in color",
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Colour::Red.paint("red"),
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Colour::Blue.paint("blue"),
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Colour::Green.paint("green"));
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}
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```
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## 加粗字体
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比颜色复杂的样式构建需要使用 `Style` 结构体:
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```rust,editable
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use ansi_term::Style;
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fn main() {
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println!("{} and this is not",
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Style::new().bold().paint("This is Bold"));
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}
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```
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## 加粗和颜色
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`Colour` 实现了很多跟 `Style` 类似的函数，因此可以实现链式调用。
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```rust,editable
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use ansi_term::Colour;
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use ansi_term::Style;
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fn main(){
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println!("{}, {} and {}",
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Colour::Yellow.paint("This is colored"),
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Style::new().bold().paint("this is bold"),
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// Colour 也可以使用 bold 方法进行加粗
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Colour::Yellow.bold().paint("this is bold and colored"));
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}
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```
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@ -1,70 +0,0 @@
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# 参数解析
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## Clap
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下面的程序给出了使用 `clap` 来解析命令行参数的样式结构，如果大家想了解更多，在 `clap` [文档](https://docs.rs/clap/)中还给出了另外两种初始化一个应用的方式。
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在下面的构建中，`value_of` 将获取通过 `with_name` 解析出的值。`short` 和 `long` 用于设置用户输入的长短命令格式，例如短命令 `-f` 和长命令 `--file`。
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```rust,editable
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use clap::{Arg, App};
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fn main() {
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let matches = App::new("My Test Program")
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.version("0.1.0")
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.author("Hackerman Jones <hckrmnjones@hack.gov>")
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.about("Teaches argument parsing")
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.arg(Arg::with_name("file")
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.short("f")
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.long("file")
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.takes_value(true)
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.help("A cool file"))
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.arg(Arg::with_name("num")
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.short("n")
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.long("number")
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.takes_value(true)
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.help("Five less than your favorite number"))
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.get_matches();
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let myfile = matches.value_of("file").unwrap_or("input.txt");
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println!("The file passed is: {}", myfile);
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let num_str = matches.value_of("num");
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match num_str {
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None => println!("No idea what your favorite number is."),
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Some(s) => {
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match s.parse::<i32>() {
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Ok(n) => println!("Your favorite number must be {}.", n + 5),
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Err(_) => println!("That's not a number! {}", s),
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}
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}
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}
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}
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```
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`clap` 针对上面提供的构建样式，会自动帮我们生成相应的使用方式说明。例如，上面代码生成的使用说明如下：
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```shell
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My Test Program 0.1.0
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Hackerman Jones <hckrmnjones@hack.gov>
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Teaches argument parsing
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USAGE:
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testing [OPTIONS]
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FLAGS:
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-h, --help Prints help information
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-V, --version Prints version information
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OPTIONS:
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-f, --file <file> A cool file
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-n, --number <num> Five less than your favorite number
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```
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最后，再使用一些参数来运行下我们的代码:
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```shell
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$ cargo run -- -f myfile.txt -n 251
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The file passed is: myfile.txt
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Your favorite number must be 256.
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```
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## Structopt
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@todo
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@ -1,3 +0,0 @@
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## 压缩
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||||
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我们会对常用的压缩方法进行介绍，例如 `tar`, `gzip`, `lz4` 等。
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@ -1,77 +0,0 @@
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# 使用tar包
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## 解压 tar 包
|
||||
以下代码将解压缩( [GzDecoder](https://docs.rs/flate2/*/flate2/read/struct.GzDecoder.html) )当前目录中的 `archive.tar.gz` ，并将所有文件抽取出( [Archive::unpack](https://docs.rs/tar/*/tar/struct.Archive.html#method.unpack) )来后当入到当前目录中。
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||||
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```rust,editable
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use std::fs::File;
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use flate2::read::GzDecoder;
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use tar::Archive;
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fn main() -> Result<(), std::io::Error> {
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let path = "archive.tar.gz";
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let tar_gz = File::open(path)?;
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let tar = GzDecoder::new(tar_gz);
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let mut archive = Archive::new(tar);
|
||||
archive.unpack(".")?;
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||||
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Ok(())
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}
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```
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## 将目录压缩成 tar 包
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以下代码将 `/var/log` 目录压缩成 `archive.tar.gz`:
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||||
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- 创建一个 [File](https://doc.rust-lang.org/std/fs/struct.File.html) 文件，并使用 [GzEncoder](https://docs.rs/flate2/*/flate2/write/struct.GzEncoder.html) 和 [tar::Builder](https://docs.rs/tar/*/tar/struct.Builder.html) 对其进行包裹
|
||||
- 通过 [Builder::append_dir_all](https://docs.rs/tar/*/tar/struct.Builder.html#method.append_dir_all) 将 `/var/log` 目录下的所有内容添加到压缩文件中，该文件在 `backup/logs` 目录下。
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- [GzEncoder](https://docs.rs/flate2/*/flate2/write/struct.GzEncoder.html) 负责在写入压缩文件 `archive.tar.gz` 之前对数据进行压缩。
|
||||
|
||||
```rust,editable
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||||
use std::fs::File;
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||||
use flate2::Compression;
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||||
use flate2::write::GzEncoder;
|
||||
|
||||
fn main() -> Result<(), std::io::Error> {
|
||||
let tar_gz = File::create("archive.tar.gz")?;
|
||||
let enc = GzEncoder::new(tar_gz, Compression::default());
|
||||
let mut tar = tar::Builder::new(enc);
|
||||
tar.append_dir_all("backup/logs", "/var/log")?;
|
||||
Ok(())
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||||
}
|
||||
```
|
||||
|
||||
## 解压的同时删除指定的文件前缀
|
||||
遍历目录中的文件 [Archive::entries](https://docs.rs/tar/*/tar/struct.Archive.html#method.entries)，若解压前的文件名包含 `bundle/logs` 前缀，需要将前缀从文件名移除( [Path::strip_prefix](https://doc.rust-lang.org/std/path/struct.Path.html#method.strip_prefix) )后，再解压。
|
||||
|
||||
|
||||
|
||||
```rust,editable
|
||||
use std::fs::File;
|
||||
use std::path::PathBuf;
|
||||
use flate2::read::GzDecoder;
|
||||
use tar::Archive;
|
||||
|
||||
fn main() -> Result<()> {
|
||||
let file = File::open("archive.tar.gz")?;
|
||||
let mut archive = Archive::new(GzDecoder::new(file));
|
||||
let prefix = "bundle/logs";
|
||||
|
||||
println!("Extracted the following files:");
|
||||
archive
|
||||
.entries()? // 获取压缩档案中的文件条目列表
|
||||
.filter_map(|e| e.ok())
|
||||
// 对每个文件条目进行 map 处理
|
||||
.map(|mut entry| -> Result<PathBuf> {
|
||||
// 将文件路径名中的前缀移除，获取一个新的路径名
|
||||
let path = entry.path()?.strip_prefix(prefix)?.to_owned();
|
||||
// 将内容解压到新的路径名中
|
||||
entry.unpack(&path)?;
|
||||
Ok(path)
|
||||
})
|
||||
.filter_map(|e| e.ok())
|
||||
.for_each(|x| println!("> {}", x.display()));
|
||||
|
||||
Ok(())
|
||||
}
|
||||
```
|
||||
@ -1 +0,0 @@
|
||||
# 配置文件 todo
|
||||
@ -1 +0,0 @@
|
||||
# 加密解密 todo
|
||||
@ -1 +0,0 @@
|
||||
# 数据库访问 todo
|
||||
@ -1 +0,0 @@
|
||||
# 时间日期
|
||||
@ -1 +0,0 @@
|
||||
# 开发调试
|
||||
@ -1 +0,0 @@
|
||||
# 日志
|
||||
@ -1 +0,0 @@
|
||||
# 性能分析
|
||||
@ -1 +0,0 @@
|
||||
# CSV
|
||||
@ -1 +0,0 @@
|
||||
# 编解码
|
||||
@ -1 +0,0 @@
|
||||
# JSON
|
||||
@ -1 +0,0 @@
|
||||
# protobuf
|
||||
@ -1 +0,0 @@
|
||||
# 目录操作
|
||||
@ -1 +0,0 @@
|
||||
# 文件读写
|
||||
@ -1 +0,0 @@
|
||||
# 文件系统 todo
|
||||
@ -1 +0,0 @@
|
||||
# gRPC
|
||||
@ -1 +0,0 @@
|
||||
# HTTP
|
||||
@ -1 +0,0 @@
|
||||
# 网络通信 todo
|
||||
@ -1 +0,0 @@
|
||||
# TCP
|
||||
@ -1 +0,0 @@
|
||||
# UDP
|
||||
@ -1 +0,0 @@
|
||||
# 正则表达式 todo
|
||||
@ -1 +0,0 @@
|
||||
# test
|
||||
@ -0,0 +1,13 @@
|
||||
# Rustt 翻译计划
|
||||
|
||||
🥇Rustt 翻译计划，这里有国内最优质、最实时的 Rust 技术文章、学习资料和新闻资讯，欢迎大家[前往阅读和订阅](https://github.com/studyrs/Rustt)。
|
||||
|
||||
## 最近优秀作品展
|
||||
|
||||
| 中文名 | 翻译时间 | 作者 |
|
||||
| ------- | -------- | ----- |
|
||||
| [series][Rust 六边形架构](https://github.com/studyrs/Rustt/tree/main/Articles/%5B2022-04-03%5D%20Rust%20六边形架构) | 2022-04-04 | [trdthg](https://github.com/trdthg) |
|
||||
| [用 Rust 写 Devops 工具](https://github.com/studyrs/Rustt/blob/main/Articles/%5B2022-04-02%5D%20用%20Rust%20写%20DevOps%20工具.md) | 2022-04-03 | [Xiaobin.Liu](https://github.com/lxbwolf) |
|
||||
| [Rust 大佬给初学者的学习建议](https://github.com/studyrs/Rustt/blob/main/Articles/%5B2022-04-02%5D%20Rust%20大佬给初学者的学习建议.md) | 2022-04-02 | [Asura](https://github.com/asur4s) |
|
||||
| [Rust 背后并不是公司](https://github.com/studyrs/Rustt/blob/main/Articles/%5B2022-04-01%5D%20Rust%20背后并不是公司.md) | 2022-04-01 | [子殊](https://github.com/allenli178) |
|
||||
| [在 Rust 中使用 epoll 实现非阻塞 IO](https://github.com/studyrs/Rustt/blob/main/Articles/%5B2022-03-29%5D%20在%20Rust%20中使用%20epoll%20实现基本的非阻塞%20IO.md) | 2022-03-29 | [BK0717](https://github.com/hyuuko) |
|
||||
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Reference in new issue