【Rust】trait-迭代器

环境

• Rust 1.56.1
• VSCode 1.61.2

概念

参考：https://doc.rust-lang.org/rust-by-example/trait/iter.html

示例

区间手动迭代

fn main() {
    // `0..3` is an `Iterator` that generates: 0, 1, and 2.
    let mut sequence = 0..3;

    println!("Four consecutive `next` calls on 0..3");
    println!("> {:?}", sequence.next());
    println!("> {:?}", sequence.next());
    println!("> {:?}", sequence.next());
    println!("> {:?}", sequence.next());
}

区间自动迭代

fn main() {
    println!("Iterate through 0..3 using `for`");
    for i in 0..3 {
        println!("> {}", i);
    }
}

Fibonacci

struct Fibonacci {
    curr: u32,
    next: u32,
}

impl Iterator for Fibonacci {
    type Item = u32;

    fn next(&mut self) -> Option<Self::Item> {
        let new_next = self.curr + self.next;

        self.curr = self.next;
        self.next = new_next;

        Some(self.curr)
    }
}

fn fibonacci() -> Fibonacci {
    Fibonacci { curr: 0, next: 1 }
}

fn main() {
    // take 限制迭代次数
    println!("The first four terms of the Fibonacci sequence are: ");
    for i in fibonacci().take(4) {
        println!("> {}", i);
    }

    // skip 跳过迭代次数
    println!("The next four terms of the Fibonacci sequence are: ");
    for i in fibonacci().skip(4).take(4) {
        println!("> {}", i);
    }
}

数组迭代

fn main() {
    let array = [1u32, 3, 3, 7];
    println!("Iterate the following array {:?}", &array);
    for i in array.iter() {
        println!("> {}", i);
    }
}

总结

了解了 Rust 中的迭代器，可以通过 for 循环来遍历迭代器。

附录