56 lines
1.4 KiB
Markdown
56 lines
1.4 KiB
Markdown
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# Strain
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Welcome to Strain on Exercism's Elixir Track.
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If you need help running the tests or submitting your code, check out `HELP.md`.
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If you get stuck on the exercise, check out `HINTS.md`, but try and solve it without using those first :)
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## Instructions
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Implement the `keep` and `discard` operation on collections.
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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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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 names in order to not clash with existing functions or concepts in your language.
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## Restrictions
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Keep your hands off that filter/reject/whatchamacallit functionality provided by your standard library!
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Solve this one yourself using other basic tools instead.
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## Source
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### Created by
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- @petehuang
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### Contributed to by
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- @angelikatyborska
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- @Cohen-Carlisle
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- @devonestes
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- @DoggettCK
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- @fxn
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- @kytrinyx
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- @neenjaw
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- @sotojuan
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### Based on
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Conversation with James Edward Gray II - http://graysoftinc.com/
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