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# Iterator::any
`Iterator::any` is a function which when passed an iterator, will return
`true` if any element satisfies the predicate. Otherwise `false`. Its
signature:
```rust,ignore
pub trait Iterator {
// The type being iterated over.
type Item;
// `any` takes `&mut self` meaning the caller may be borrowed
// and modified, but not consumed.
fn any<F>(&mut self, f: F) -> bool where
// `FnMut` meaning any captured variable may at most be
// modified, not consumed. `Self::Item` states it takes
// arguments to the closure by value.
F: FnMut(Self::Item) -> bool;
}
```
```rust,editable
fn main() {
let vec1 = vec![1, 2, 3];
let vec2 = vec![4, 5, 6];
// `iter()` for vecs yields `&i32`. Destructure to `i32`.
println!("2 in vec1: {}", vec1.iter() .any(|&x| x == 2));
// `into_iter()` for vecs yields `i32`. No destructuring required.
println!("2 in vec2: {}", vec2.into_iter().any(|x| x == 2));
// `iter()` only borrows `vec1` and its elements, so they can be used again
println!("vec1 len: {}", vec1.len());
println!("First element of vec1 is: {}", vec1[0]);
// `into_iter()` does move `vec2` and its elements, so they cannot be used again
// println!("First element of vec2 is: {}", vec2[0]);
// println!("vec2 len: {}", vec2.len());
// TODO: uncomment two lines above and see compiler errors.
let array1 = [1, 2, 3];
let array2 = [4, 5, 6];
// `iter()` for arrays yields `&i32`.
println!("2 in array1: {}", array1.iter() .any(|&x| x == 2));
// `into_iter()` for arrays yields `i32`.
println!("2 in array2: {}", array2.into_iter().any(|x| x == 2));
}
```
### See also:
[`std::iter::Iterator::any`][any]
[any]: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.any
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