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