Rust Vec与迭代器以及Option遍历Vec 直接遍历Vec 使用迭代器向Vec中添加元素向Vec中添加可选原

遍历Vec

直接遍历Vec

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

let mut v = vec![1, 2, 3];
for i in &mut v {
    *i += 50;
}

使用迭代器

let v1 = vec![1, 2, 3];
let v1_iter = v1.iter();

for val in v1_iter {
    println!("Got: {}", val);
}

let mut v1 = vec![1, 2, 3];
let v1_iter = v1.iter_mut();
for val in v1_iter {
    *val += 50;
}

向Vec中添加元素

let grade = "A+";
let mut grades = vec!["B-", "C+", "D"];
grades.push(grade)

向Vec中添加可选原色

let grade = Some("A+");
let mut grades = vec!["B-", "C+", "D"];

// 方式一
if let Some(grade) = grade {
  grades.push(grade)
}

// 方式二
grades.extend(grade);

迭代器的一些应用

// Extend an iterator
let grade = Some("A+");
let grades = vec!["B-", "C+", "D"];
for grade in grades.iter().chain(grade.iter()) {
    println!("{grade}");
}

// Filter out non variants
let grades = vec![Some("A+"), None, Some("B+"), None];
let grades: Vec<&str> = grades.into_iter().flatten().collect();
println!("{grades:?}");

// Map and filter out non variants
let grades = ["3.8", "B+", "4.0", "A", "2.7"];
let grades: Vec<f32> = grades.iter().filter_map(|s| s.parse().ok()).collect();
println!("{grades:?}");

迭代器区别

iter: 普通迭代器
iter_mut: 可变迭代器，用于修改迭代器元素
into_iter: 获取所有权迭代器，用于构建新迭代器

Rust Vec与迭代器以及Option

遍历Vec

向Vec中添加元素

向Vec中添加可选原色

迭代器的一些应用

迭代器区别

参考