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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 .
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Source
Conversation with James Edward Gray II https://twitter.com/jeg2
Submitting Incomplete Problems
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