πππ The `@` operator lets us create a variable that holds a value at the same time we are testing that value to see whether it matches a pattern.
```rust,editable
struct Point {
x: i32,
y: i32,
}
fn main() {
// fill in the blank to let p match the second arm
let p = Point { x: __, y: __ };
match p {
Point { x, y: 0 } => println!("On the x axis at {}", x),
// second arm
Point { x: 0..=5, y: y@ (10 | 20 | 30) } => println!("On the y axis at {}", y),
Point { x, y } => println!("On neither axis: ({}, {})", x, y),
}
}
```
πππ
```rust,editable
// fix the errors
enum Message {
Hello { id: i32 },
}
fn main() {
let msg = Message::Hello { id: 5 };
match msg {
Message::Hello {
id: 3..=7,
} => println!("Found an id in range [3, 7]: {}", id),
Message::Hello { id: newid@10 | 11 | 12 } => {
println!("Found an id in another range [10, 12]: {}", newid)
}
Message::Hello { id } => println!("Found some other id: {}", id),
}
}
```
ππ A match guard is an additional if condition specified after the pattern in a match arm that must also match, along with the pattern matching, for that arm to be chosen.
```rust,editable
// fill in the blank to make the code work, `split` MUST be used
fn main() {
let num = Some(4);
let split = 5;
match num {
Some(x) __ => assert!(x <split),
Some(x) => assert!(x >= split),
None => (),
}
}
```
ππ Ignoring remaining parts of the value with `..`