# Strain Implement the `keep` and `discard` operation on collections. Given a collection and a predicate on the collection's elements, `keep` returns a new collection containing those elements where the predicate is true, while `discard` returns a new collection containing those elements where the predicate is false. Write two functions that each take a function and a list. One of them will return the list of items for which the passed in function is true, and the other will return the items for which it is false. For example, given the collection of numbers: - 1, 2, 3, 4, 5 And the predicate: - is the number even? Then your keep operation should produce: - 2, 4 While your discard operation should produce: - 1, 3, 5 Note that the union of keep and discard is all the elements. The functions may be called `keep` and `discard`, or they may need different names in order to not clash with existing functions or concepts in your language. ## Restrictions Keep your hands off that filter/reject/whatchamacallit functionality provided by your standard library! Solve this one yourself using other basic tools instead. To run the tests simply run the command `go test` in the exercise directory. If the test suite contains benchmarks, you can run these with the `-bench` flag: go test -bench . For more detailed info about the Go track see the [help page](http://exercism.io/languages/go). ## Source Conversation with James Edward Gray II [https://twitter.com/jeg2](https://twitter.com/jeg2) ## Submitting Incomplete Problems It's possible to submit an incomplete solution so you can see how others have completed the exercise.