functional-programing/iterator

[giscus[bot]]

functional-programing/iterator

Learning Rust By Practice, narrowing the gap between beginner and skilled-dev with challenging examples, exercises and projects.

https://zh.practice.rs/functional-programing/iterator.html

[tabris233]

催更

[LilMikey-CN]

催更

[AllenWu233]

习题在英文版：https://practice.course.rs/functional-programing/iterator.html
答案：https://github.com/sunface/rust-by-practice/blob/master/solutions/functional-programing/iterator.md

[gastrodia]

1

fn main() {
    let arr = [0; 10];
    for i in arr.iter() {
        println!("{}", i);
    }
}

---

2

fn main() {
    let mut v = Vec::new();
    for n in __ {
       v.push(n);
    }

    assert_eq!(v.len(), 100);
}

---

3

fn main() {
    let v1 = vec![1, 2];
    let mut v1 = v1.into_iter();

    assert_eq!(v1.next(), Some(1));
    assert_eq!(v1.next(), Some(2));
    assert_eq!(v1.next(), None);
}

---

4

fn main() {
    let arr = vec![0; 10];
    for i in arr.iter() {
        println!("{}", i);
    }

    println!("{:?}",arr);
}

---

5

fn main() {
    let mut names = vec!["Bob", "Frank", "Ferris"];

    for name in names.iter_mut(){
        *name = match name {
            &mut "Ferris" => "There is a rustacean among us!",
            _ => "Hello",
        }
    }

    println!("names: {:?}", names);
}

---

6

/* Fill in the blank */
fn main() {
    let mut values = vec![1, 2, 3];
    let mut values_iter = values.__;

    if let Some(v) = values_iter.__{
        __
    }

    assert_eq!(values, vec![0, 2, 3]);
}

---

7

  fn next(&mut self) -> Option<u32> {
        let new_next = self.curr + self.next;
        self.curr = self.next;
        self.next = new_next;
        Some(self.curr)
    }

---

8

fn main() {
    let v1 = vec![1, 2, 3];

    let v1_iter = v1.iter();

    // The sum method will take the ownership of the iterator and iterates through the items by repeatedly calling next method
    let total = v1_iter.sum::<i32>();

    assert_eq!(total, 6);

    println!("{:?}",v1);
}

---

9

fn main() {
    let names = [("sunface",18), ("sunfei",18)];
    let folks: HashMap<_, _> = names.into_iter().collect();

    println!("{:?}",folks);

    let v1: Vec<i32> = vec![1, 2, 3];

    let v2: Vec<_> = v1.into_iter().collect();

    assert_eq!(v2, vec![1, 2, 3]);
}

---

10

fn main() {
    let v1: Vec<i32> = vec![1, 2, 3];

    let v2: Vec<_> = v1.iter().map(|x| x+1).collect();

    assert_eq!(v2, vec![2, 3, 4]);
}

---

11

fn main() {
    let names = ["sunface", "sunfei"];
    let ages = [18, 18];
    let folks: HashMap<_, _> = names.into_iter().zip(ages.into_iter()).collect();

    println!("{:?}",folks);

---

12

fn shoes_in_size(shoes: Vec<Shoe>, shoe_size: u32) -> Vec<Shoe> {
    shoes.into_iter().filter(|x| x.size == shoe_size).collect()
}

[FlandreLiao]

done