There is no such helper method on the Iterator trait directly. However, there are two main ways to do it: Use the [T]::chunks() method (which can be called on a Vec<T> directly). However, it has a minor difference: it won’t produce None, but the last iteration yields a smaller slice. For always-exact slices that omit … 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
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
Update: in recent versions of Photoshop, there is a built-in option to export the image as SVG, which works well on paths and custom shapes. Just do: File -> Export -> Export as… and select SVG in the file settings. Original Answer: Starting from Photoshop CC 14.2, you can create SVG files directly from Photoshop: … Read more
You need slice patterns: fn vec_alt<T>(vals: Vec<T>) -> &’static str { match vals[..] { [a, b] => “two elements”, [a, b, c] => “three elements”, _ => “otherwise”, } }
Use drain to remove multiple contiguous elements from a vector at once as efficiently as possible (the implementation uses ptr::copy to move the elements that remain): let mut v = vec![1, 2, 3, 4]; v.drain(0..2); assert!(v == vec![3, 4]); Regarding #2, it is not feasible to avoid shifting the remaining elements. That optimization would require … Read more
That’s not how predicates work. You have to supply either a free function bool Comparator(const MyClass & m) { … }, or build a function object, a class that overloads operator(): struct MyClassComp { explicit MyClassComp(int i) n(i) { } inline bool operator()(const MyClass & m) const { return m.myInt == n; } private: int … 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
One informal but rather intuitive way to think about this is to consider the 2 components of a vector: direction and magnitude. Direction is the “preference”https://stackoverflow.com/”style”https://stackoverflow.com/”sentiment”https://stackoverflow.com/”latent variable” of the vector, while the magnitude is how strong it is towards that direction. When classifying documents we’d like to categorize them by their overall sentiment, so we … Read more
You can use slice::last: fn top(&mut self) -> Option<f64> { self.last().copied() } Option::copied (and Option::cloned) can be used to convert from an Option<&f64> to an Option<f64>, matching the desired function signature. You can also remove the mut from both the implementation and the trait definition.