rust与python/c++语法区别

if / match

pub fn animal_habitat(animal: &str) -> &'static str {
    let id = if animal == "crab" {  //id等于(或拥有)了一个匿名函数的返回值
        1
    } else if animal == "gopher" {
        2
    } else if animal == "snake" {
        3
    } else {
        -1
    };
}

match number {
    // 匹配单个值
    1 => println!("One!"),
    // 匹配多个值
    2 | 3 | 5 | 7 | 11 => println!("This is a prime"),
    // 匹配一个闭区间范围
    13..=19 => println!("A teen"),
    // else
    _ => println!("Ain't special"),
    }

for while loop

    for n in 1..101 {}
    for n in 1..=100 {}
    for number in (1..101).rev() {}
    for name in names.iter() {}
    for name in names.into_iter() {}
    for name in names.iter_mut() {}

    'counting_up: loop {
	loop {
            if id == 1 {
                break;
            }
            if id == 2 {
                break 'counting_up;
            }
        }

slice array tuple

fn slice_out_of_array() {
    let mut a :[i32] = [0; 100];  //100个0，[i32]表i32的数组

    let a = [1, 2, 3, 4, 5];  //遮蔽shadow，变量另用
    let nice_slice = &a[1..4];
    //slice前面要加&
}

fn indexing_tuple() {
    let numbers = (1, 2, 3);

    let second = numbers.1;  //成员
    let (a,b,c)=numbers;  //拆解tuple
}

vector

数组array的空间已知，分配到内存的栈Stack部分；
向量vector空间未知，可以随意拓展/收缩空间，分配到堆Heap。

fn array_and_vec() -> ([i32; 4], Vec<i32>) {
    let a = [10, 20, 30, 40]; // a plain array
    let v = vec![10, 20, 30, 40];  //macro for vectors

    (a, v)
}