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Contents

# 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.

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.

`apply` will let you pass arguments to a function, as will `fun.(args)`


## Running tests

Execute the tests with:

```bash
$ elixir bob_test.exs
```

(Replace `bob_test.exs` with the name of the test file.)

### Pending tests

In the test suites, all but the first test have been skipped.

Once you get a test passing, you can unskip the next one by
commenting out the relevant `@tag :pending` with a `#` symbol.

For example:

```elixir
# @tag :pending
test "shouting" do
  assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"
end
```

Or, you can enable all the tests by commenting out the
`ExUnit.configure` line in the test suite.

```elixir
# ExUnit.configure exclude: :pending, trace: true
```

For more detailed information about the Elixir track, please
see the [help page](http://exercism.io/languages/elixir).

## Source

Conversation with James Edward Gray II [https://twitter.com/jeg2](https://twitter.com/jeg2)

## Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.

Version data entries

96 entries across 96 versions & 1 rubygems

Version Path
trackler-2.2.1.71 tracks/elixir/exercises/strain/README.md
trackler-2.2.1.70 tracks/elixir/exercises/strain/README.md
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trackler-2.2.1.68 tracks/elixir/exercises/strain/README.md
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trackler-2.2.1.66 tracks/elixir/exercises/strain/README.md
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trackler-2.2.1.60 tracks/elixir/exercises/strain/README.md
trackler-2.2.1.59 tracks/elixir/exercises/strain/README.md
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trackler-2.2.1.52 tracks/elixir/exercises/strain/README.md