1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
% Slice patterns
If you want to match against a slice or array, you can use `&` with the
`slice_patterns` feature:
```rust
#![feature(slice_patterns)]
fn main() {
let v = vec!["match_this", "1"];
match &v[..] {
&["match_this", second] => println!("The second element is {}", second),
_ => {},
}
}
```
The `advanced_slice_patterns` gate lets you use `..` to indicate any number of
elements inside a pattern matching a slice. This wildcard can only be used once
for a given array. If there's an identifier before the `..`, the result of the
slice will be bound to that name. For example:
```rust
#![feature(advanced_slice_patterns, slice_patterns)]
fn is_symmetric(list: &[u32]) -> bool {
match list {
&[] | &[_] => true,
&[x, ref inside.., y] if x == y => is_symmetric(inside),
_ => false
}
}
fn main() {
let sym = &[0, 1, 4, 2, 4, 1, 0];
assert!(is_symmetric(sym));
let not_sym = &[0, 1, 7, 2, 4, 1, 0];
assert!(!is_symmetric(not_sym));
}
```
|
