Effect:  If count <= size(), erase the last size() - count elements  If count > size(), append (count - size()) default-initialized elements  Invokes r = op(data(), count)  Invokes erase(begin() // false69 Changes to Ranges Library  ranges::shift_left() / ranges::shift_right() Shifts the elements in a range left or right  E.g.: std::vector v{ "a", "b", "c", "d", "e"};// "a", element a tuple of the nth elements of all given views  views::zip_transform: A view with the nth element the result of applying a given operator to the nth elements of all given views  E.g.:

September 18 • 12:00Ranges11 Ranges  What’s a range?  An object referring to a sequence/range of elements  Similar to a begin/end iterator pair, but does not replace them  Why ranges?  Provide nicer begin/end iterators  Allows “range adaptors” to lazily transform/filter underlying sequences of elements12 Ranges  Based on following major components:  Range: A concept defining iteration requirements Standard Library algorithms accepting ranges instead of iterator pairs  Projection: Transform elements before handing over to algorithm  Views: transform/filter range: lazily evaluated, non-owning

continue; } // ... } }15 Erasing Elements16 Container Erasure Strategies • Erasing unwanted elements before C++20: • vector-like: erase-remove idiom • list-like: remove/remove_if Quadratic complexity vec.erase(iter) loop 🐞 • Invalidating iterators while looping 🐞 • Skipping elements while looping 🐞17 Uniform Container Erasure • GH-236 and GH-566 implemented by SuperWig #include read, 1729 }21 span22 span Encapsulates Ptr-Len Pairs • span is a non-owning view of contiguous elements • span is like a pair of T* and size_t, but better • spans are implicitly constructible from

Magical Flag Why fast? Clickhouse Mutation Trouble Shoot ● SQL is too big(max_ast_elements, max_expanded_ast_elements) ● Mutations are stuck (KILL MUTATION) ● Zookeeper OOM because of SQL length (Put ids

Concepts Let’s look at the and Defining Views Pages/Views o XML markup structure o Elements (e.g. , ) are NativeScript modules NativeScript Modules for UIs UI Widgets o Button Safari AppInspector iOS Chrome DevTools VSCode Extension Debugger Console Resources Network Elements Memory Profiling Timeline/CPU Prof. Anything Else? Two easy ways to use NativeScript 1) 2) NativeScript

CPU will have to wait. What if the application needs fast access to neighboring data, rather than elements in a row, or must transverse the data multiple times? • To improve data locality of multi-dimensional