2022-11-06 22:06:19 -06:00
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1.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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fn main() {
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let arr = [0; 10];
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for i in arr {
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println!("{}", i)
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}
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}
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```
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2022-11-06 22:06:19 -06:00
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2.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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fn main() {
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let mut v = Vec::new();
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for n in 1..101 {
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v.push(n);
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}
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assert_eq!(v.len(), 100);
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}
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```
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2022-11-06 22:06:19 -06:00
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3.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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fn main() {
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let v1 = vec![1, 2];
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// moving ownership
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let mut v1_iter = v1.into_iter();
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assert_eq!(v1_iter.next(), Some(1));
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assert_eq!(v1_iter.next(), Some(2));
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assert_eq!(v1_iter.next(), None);
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}
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```
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```rust
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fn main() {
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let v1 = vec![1, 2];
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// borrowing
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let mut v1_iter = v1.iter();
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assert_eq!(v1_iter.next(), Some(&1));
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assert_eq!(v1_iter.next(), Some(&2));
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assert_eq!(v1_iter.next(), None);
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}
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```
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2022-11-06 22:06:19 -06:00
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4.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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fn main() {
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let arr = vec![0; 10];
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for i in arr.iter() {
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println!("{}", i)
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}
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println!("{:?}",arr);
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}
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```
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2022-11-06 22:06:19 -06:00
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5.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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fn main() {
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let mut names = vec!["Bob", "Frank", "Ferris"];
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for name in names.iter_mut() {
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*name = match name {
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&mut "Ferris" => "There is a rustacean among us!",
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_ => "Hello",
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}
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}
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println!("names: {:?}", names);
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}
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```
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2022-11-06 22:06:19 -06:00
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6.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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fn main() {
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let mut values = vec![1, 2, 3];
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let mut values_iter = values.iter_mut();
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if let Some(v) = values_iter.next() {
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*v = 0;
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}
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assert_eq!(values, vec![0, 2, 3]);
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}
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```
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2022-11-06 22:06:19 -06:00
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7.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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struct Fibonacci {
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curr: u32,
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next: u32,
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}
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// Implement `Iterator` for `Fibonacci`.
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// The `Iterator` trait only requires a method to be defined for the `next` element.
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impl Iterator for Fibonacci {
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// We can refer to this type using Self::Item
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type Item = u32;
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// Here, we define the sequence using `.curr` and `.next`.
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// The return type is `Option<T>`:
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// * When the `Iterator` is finished, `None` is returned.
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// * Otherwise, the next value is wrapped in `Some` and returned.
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// We use Self::Item in the return type, so we can change
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// the type without having to update the function signatures.
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fn next(&mut self) -> Option<Self::Item> {
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let new_next = self.curr + self.next;
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self.curr = self.next;
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self.next = new_next;
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// Since there's no endpoint to a Fibonacci sequence, the `Iterator`
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// will never return `None`, and `Some` is always returned.
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Some(self.curr)
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}
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}
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// Returns a Fibonacci sequence generator
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fn fibonacci() -> Fibonacci {
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Fibonacci { curr: 0, next: 1 }
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}
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fn main() {
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let mut fib = fibonacci();
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assert_eq!(fib.next(), Some(1));
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assert_eq!(fib.next(), Some(1));
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assert_eq!(fib.next(), Some(2));
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assert_eq!(fib.next(), Some(3));
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assert_eq!(fib.next(), Some(5));
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}
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```
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2022-11-06 22:06:19 -06:00
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8.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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fn main() {
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let v1 = vec![1, 2, 3];
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let v1_iter = v1.iter();
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// The sum method will take the ownership of the iterator and iterates through the items by repeatedly calling next method
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let total: i32 = v1_iter.sum();
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assert_eq!(total, 6);
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println!("{:?}",v1);
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}
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```
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2022-11-06 22:06:19 -06:00
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9.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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use std::collections::HashMap;
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fn main() {
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let names = [("sunface",18), ("sunfei",18)];
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let folks: HashMap<_, _> = names.into_iter().collect();
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println!("{:?}",folks);
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let v1: Vec<i32> = vec![1, 2, 3];
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let v2: Vec<_> = v1.into_iter().collect();
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assert_eq!(v2, vec![1, 2, 3]);
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}
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```
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2022-11-06 22:06:19 -06:00
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10.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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fn main() {
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let v1: Vec<i32> = vec![1, 2, 3];
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let v2: Vec<_> = v1.iter().map(|x| x + 1).collect();
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assert_eq!(v2, vec![2, 3, 4]);
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}
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```
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2022-11-06 22:06:19 -06:00
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11.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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use std::collections::HashMap;
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fn main() {
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let names = ["sunface", "sunfei"];
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let ages = [18, 18];
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let folks: HashMap<_, _> = names.into_iter().zip(ages.into_iter()).collect();
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println!("{:?}",folks);
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}
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```
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2022-11-06 22:06:19 -06:00
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12.
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2022-05-01 00:08:50 -05:00
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2022-03-31 02:43:23 -06:00
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```rust
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#[derive(PartialEq, Debug)]
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struct Shoe {
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size: u32,
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style: String,
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}
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fn shoes_in_size(shoes: Vec<Shoe>, shoe_size: u32) -> Vec<Shoe> {
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shoes.into_iter().filter(|s| s.size == shoe_size).collect()
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}
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fn main() {
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let shoes = vec![
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Shoe {
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size: 10,
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style: String::from("sneaker"),
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},
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Shoe {
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size: 13,
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style: String::from("sandal"),
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},
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Shoe {
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size: 10,
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style: String::from("boot"),
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},
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];
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let in_my_size = shoes_in_size(shoes, 10);
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assert_eq!(
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in_my_size,
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vec![
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Shoe {
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size: 10,
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style: String::from("sneaker")
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},
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Shoe {
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size: 10,
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style: String::from("boot")
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},
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]
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);
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}
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```
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