If you want to remove elements, you can use retain(), which removes elements from the vector if the closure returns false: let mut vec = vec![1, 2, 3, 4]; vec.retain(|&x| x % 2 == 0); assert_eq!(vec, [2, 4]); If you want to modify the elements in place, you have to do that in a for … Read more
They are somewhat redundant with each other. However, as you say, Drain just borrows the vector, in particular, it has a lifetime connected with the vector. If one is wishing to return an iterator, or otherwise munge iterators in the most flexible way possible, using into_iter is better, since it’s not chained to the owner … Read more
The type &(&str, &str) comes from what iter() on a Vec returns: fn iter(&self) -> Iter<T> where Iter<T> implements Iterator<Item=&T>: impl<‘a, T> Iterator for Iter<‘a, T> { type Item = &’a T … } In other words, iter() on a vector returns an iterator yielding references into the vector. cloned() solves the problem because it … Read more
No, there is no trait that provides iter(). However, IntoIterator is implemented on references to some containers. For example, Vec<T>, &Vec<T> and &mut Vec<T> are three separate types that implement IntoIterator, and you’ll notice that they all map to different iterators. In fact, Vec::iter() and Vec::iter_mut() are just convenience methods equivalent to &Vec::into_iter() and &mut … Read more
Turns out the .skip() method can be used, eg: use std::env; fn main() { for arg in env::args().skip(1) { println!(“Argument: {}”, arg); } }
An iterator traverses a collection one at a time. A generator generates a sequence, one item at a time. You might for example, iterate over the result of a generator…
No, a vector is not an iterator. But it implements the trait IntoIterator, which the for loop uses to convert the vector into the required iterator. In the documentation for Vec you can see that IntoIterator is implemented in three ways: for Vec<T>, which is moved and the iterator returns items of type T, for … Read more
You can remove the reference by destructuring in the pattern: // | // v for &var in slice { other_fn(var); } However, this only works for Copy-types! If you have a type that doesn’t implement Copy but does implement Clone, you could use the cloned() iterator adapter; see Chris Emerson’s answer for more information.
In your particular case, it’s because you have implemented your trait for an iterator of String, but your vector is providing an iterator of &str. Here’s a more generic version: use std::collections::HashSet; use std::hash::Hash; struct Unique<I> where I: Iterator, { seen: HashSet<I::Item>, underlying: I, } impl<I> Iterator for Unique<I> where I: Iterator, I::Item: Hash + … Read more
As far as I understand, you want want the iterator to return a vector of references into itself, right? Unfortunately, it is not possible in Rust. This is the trimmed down Iterator trait: trait Iterator { type Item; fn next(&mut self) -> Option<Item>; } Note that there is no lifetime connection between &mut self and … Read more