:: (a -> Bool) -> [a] -> [a] -is:exact -is:exact -is:exact package:daml-stdlib -is:exact

A version of `dropWhile` operating from the end.

A version of `takeWhile` operating from the end.

Take elements from a list while the predicate holds.

Drop elements from a list while the predicate holds.

Filters the list using the function: keep only the elements where the predicate holds.

Sort a list by comparing the results of a key function applied to each element. `sortOn f` is equivalent to `sortBy (comparing f)`, but has the performance advantage of only evaluating `f` once for each element in the input list. This is sometimes called the decorate-sort-undecorate paradigm. Elements are arranged from from lowest to highest, keeping duplicates in the order they appeared in the input.

A version of `dedup` where deduplication is done after applyng function. Example use: `dedupOn (.employeeNo) employees`

A version of `dedup` where deduplication is done after applying the given function. Example use: `dedupOn (.employeeNo) employees`. `dedupOn` is stable so the elements in the output are ordered by their first occurrence in the input. If you do not need stability, consider using `dedupOnSort` which is more efficient. ``` >>> dedupOn fst [(3, "a"), (1, "b"), (1, "c"), (3, "d")] [(3, "a"), (1, "b")] ```

`dedupOnSort` is a more efficient variant of `dedupOn` that does not preserve the order of the input elements. Instead the output will be sorted on the values returned by the function. For duplicates, the first element in the list will be included in the output. ``` >>> dedupOnSort fst [(3, "a"), (1, "b"), (1, "c"), (3, "d")] [(1, "b"), (3, "a")] ```

`sortOn f` is a version of sort that allows sorting on the result of the given function. `sortOn` is stable so elements that map to the same sort key will be ordered by their position in the input. ``` >>> sortOn fst [(3, "a"), (1, "b"), (3, "c"), (2, "d")] [(1, "b"), (2, "d"), (3, "a"), (3, "c")] ```