doc: update rust.md #50 #49

This commit is contained in:
jaywcjlove 2022-11-12 00:53:33 +08:00
parent 5677612d9d
commit 4ce6660ca8

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@ -19,6 +19,7 @@ fn main() {
```shell
$ rustc Hello_World.rs
$ ./Hello_World
Hello, World!
```
@ -396,48 +397,8 @@ println!("{:?}", str4);
Rust 动态数组
-----------
### 创建动态数组
```rust
let v: Vec<i32> = Vec::new();
// 使用宏
let v1 = vec![1, 2, 3];
```
### 读取元素
```rust
let v = vec![1, 2, 3, 4, 5];
let element = &v[100];
// panic越界
let element2 = v.get(100);
println!("{:?}", element2);
//None
```
### 遍历数组
1. 只读取数组中的元素
```rust
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
```rust
let mut v = vec![1, 2, 3];
for i in &mut v {
*i += 10
}
```
### 常用方法
<!--rehype:wrap-class=col-span-3-->
<!--rehype:wrap-class=col-span-2 row-span-2-->
-|:-
-|:-
@ -454,6 +415,45 @@ println!("{:?}", element2);
`drain(range)` | 删除 `vec` 中指定范围的元素,同时返回一个迭代该范围所有元素的迭代器
`split_off(index)` | 切分 `vec`,索引左边的元素保留在原 `vec` 中(含索引),索引右边的元素(不含索引)在返回的 `vec`
### 创建动态数组
```rust
let v: Vec<i32> = Vec::new();
// 使用宏
let v1 = vec![1, 2, 3];
```
### 遍历数组
只读取数组中的元素
```rust
let v = vec![1, 2, 3];
for i in &v {
println!("{}", i);
}
```
遍历的同时修改数组中的元素
```rust
let mut v = vec![1, 2, 3];
for i in &mut v {
*i += 10
}
```
### 读取元素
```rust
let v = vec![1, 2, 3, 4, 5];
let element = &v[100];
// panic越界
let element2 = v.get(100);
println!("{:?}", element2);
//None
```
Rust 运算符
-----------
@ -527,8 +527,8 @@ let left_shift = h << 4; // => 32
示例 | 意义
:- | :-
`c && d` | 两者都是真的_(AND)_
`c || d` | 要么是真的_(OR)_
`c && d` | 两者都是真的 _(AND)_
`c \|\| d` | 要么是真的 _(OR)_
`!c` | `c` 为假 _(NOT)_
----
@ -754,15 +754,15 @@ fn main(){
```rust
struct Point {
x: i32,
y: i32,
z: i32,
x: i32,
y: i32,
z: i32,
}
let origin = Point { x: 0, y: 0, z: 0 };
match origin {
Point { x, .. } => println!("x is {}", x),
Point { x, .. } => println!("x is {}", x),
}
```
@ -772,9 +772,9 @@ match origin {
let hello = ('h', 'e', 'l', 'l', 'o');
match hello {
(h, _, _, l, o) => {
println!("char: {}, {}, {}", h, l, o)
},
(h, _, _, l, o) => {
println!("char: {}, {}, {}", h, l, o)
},
}
```
@ -785,9 +785,9 @@ match hello {
```rust
let x = Some(10);
match x {
Some(1) => println!("x = 1"),
Some(y) => println!("y = {:?}", y),
_ => println!("None"),
Some(1) => println!("x = 1"),
Some(y) => println!("y = {:?}", y),
_ => println!("None"),
}// y = 10
```
@ -799,25 +799,27 @@ match x {
```rust
let grade = 'A';
match grade {
good @ 'A'..='C' => println!("your grade is {}", good),
_ => println!("Come on"),
good @ 'A'..='C' => println!("your grade is {}", good),
_ => println!("Come on"),
}
```
<!--rehype:className=wrap-text -->
----
```rust
#[derive(Debug)]
struct Point {
x: i32,
y: i32,
x: i32,
y: i32,
}
fn main(){
let p @ Point {x: px, y: py } = Point {x: 10, y: 23};
println!("x: {}, y: {}", px, py);
println!("{:?}", p);
let p @ Point {x: px, y: py } = Point {x: 10, y: 23};
println!("x: {}, y: {}", px, py);
println!("{:?}", p);
}
```
<!--rehype:className=wrap-text -->
----
@ -825,10 +827,10 @@ fn main(){
```rust
match 1 {
num @ (1 | 2) => {
println!("{}", num);
}
_ => {}
num @ (1 | 2) => {
println!("{}", num);
}
_ => {}
}
```
@ -837,11 +839,12 @@ match 1 {
```rust
let x = Some(2);
match x {
Some(1) => println!("x = 1"),
Some(y) if y == 2 => println!("y = {:?}", y),
_ => println!("No match"),
Some(1) => println!("x = 1"),
Some(y) if y == 2 => println!("y = {:?}", y),
_ => println!("No match"),
}// y = 2
```
<!--rehype:className=wrap-text -->
Rust 函数
--------
@ -857,21 +860,23 @@ fn print_message(){
```
### 参数值
<!--rehype:wrap-class=row-span-2-->
rust 需要为函数的参数标明确定的类型
```rust
fn another_fn(a:u8, b: &str){
println!("我是 u8:{}", a);
println!("我是 &str:{}", b);
println!("我是 u8:{}", a);
println!("我是 &str:{}", b);
}
fn main(){
another_fn(10, "hello")
another_fn(10, "hello")
}
```
### 返回值
<!--rehype:wrap-class=row-span-2-->
如果不指定返回值rust 默认返回 `()` 类型
@ -880,16 +885,14 @@ fn main(){
fn main(){}
```
----
使用 `->` 指定返回值,如果**表达式**在最后一行,无需使用 return
使用 `->` 指定返回值,如果**表达式**在最后一行,无需使用 `return`
```rust
fn add(a:i32, b:i32) -> i32 {
if a + b < 100 {
return a - b;
}
a + b
if a + b < 100 {
return a - b;
}
a + b
}
```