It’s very important programming skill to learn how to create a minimal, reproducible example. Your problem can be reduced to this: struct Vocabulary; fn main() { let numbers = vec![Vocabulary]; let other_numbers: Vec<Vocabulary> = numbers.iter().collect(); } Let’s look at the error message for your case: error[E0277]: a collection of type `std::vec::Vec<Vocabulary>` cannot be built from … Read more
subvec is probably the best way. The Clojure docs say subvec is “O(1) and very fast, as the resulting vector shares structure with the original and no trimming is done“. The alternative would be walking the vector and building a new one while skipping certain elements, which would be slower. Removing elements from the middle … Read more
How do I work around You don’t “work around” this type of problem. Ownership is a fundamental concept in Rust and you have to understand it. Solutions Make your Card implicitly copyable via Copy #[derive(Debug, Copy, Clone)] enum Card { /* … */ } Make your Card explicitly copyable via Clone #[derive(Debug, Clone)] enum Card … Read more
If you do not want to create a wrapper type you can use the ordered_float or ord_subset crate. For example extern crate ordered_float; extern crate ord_subset; #[test] fn test_example_() { use ordered_float::OrderedFloat; // OrderedFloat -> NaN is greater than all other values and equal to itself. // NotNaN -> NotNaN::new panics if called with NaN. … Read more
You can write your function like this: fn take<T>(mut vec: Vec<T>, index: usize) -> Option<T> { if vec.get(index).is_none() { None } else { Some(vec.swap_remove(index)) } } The code you see here (get and swap_remove) is guaranteed O(1). However, kind of hidden, vec is dropped at the end of the function and this drop operation is … Read more
The structure std::vec::Vec has method append(): fn append(&mut self, other: &mut Vec<T>) Moves all the elements of other into Self, leaving other empty. From your example, the following code will concatenate two vectors by mutating a and b: fn main() { let mut a = vec![1, 2, 3]; let mut b = vec![4, 5, 6]; … Read more
The camera does not have a “look vector”, so you cannot set it. You can, however, construct a point to look at by adding your look vector to the camera’s position, and then calling camera.lookAt( point ); Here is how to determine the direction in which the camera is looking, assuming the camera either has … Read more
You can sort indices_to_update and extract mutable references by calling split_*_mut. let len = big_vector_of_elements.len(); while has_things_to_do() { let mut tail = big_vector_of_elements.as_mut_slice(); let mut indices_to_update = compute_indices(); // I assumed compute_indices() returns unsorted vector // to highlight the importance of sorted order indices_to_update.sort(); let mut elems = Vec::new(); for idx in indices_to_update { // … Read more
This article gives more details about this issue: http://electrosofts.com/systemverilog/arrays.html, especially section 5.2. A packed array is a mechanism for subdividing a vector into subfields which can be conveniently accessed as array elements. Consequently, a packed array is guaranteed to be represented as a contiguous set of bits. An unpacked array may or may not be … Read more