Elixir convert string to map code not working

Question

Good day developers, i'm having issues figuring out how to make a function work.

Test case

  test "count one of each" do
    expected = %{"one" => 1, "of" => 1, "each" => 1}
    assert Words.count("one of each") == expected
  end

And this is what i came up with so far.

@spec count(String.t()) :: map
  def count(sentence) do
    sentence
    |> String.split
    |> Enum.map([sentence], &(%{sentence => 1 , value =>&1}))
  end
end

The code itself doesn't work, can some one explain how can i achieve the following functionality based on the test i provided?

Big thanks.

Questions seeking debugging help ("why isn't this code working?") must include the desired behavior, a specific problem or error and the shortest code necessary to reproduce it in the question itself. Questions without a clear problem statement are not useful to other readers. See: How to create a Minimal, Complete, and Verifiable example. — scopchanov
– scopchanov, Commented Sep 30, 2018 at 13:34

Adam Millerchip · Accepted Answer · 2019-03-20 01:05:20Z

4

From your code it looks like you haven't understood how pipes |> or the Enum functions work. It would probably benefit you to read the documentation in more detail.

This should do what you want:

"one of each"
|> String.split()
|> Enum.group_by(fn x -> x end)
|> Enum.map(fn {k, v} -> {k, length(v)} end) 
|> Enum.into(%{})

Explanation:

Split the string into a list.
Group the list into a map. The keys are the words, the value is a list containing each occurrence.
Convert each list into a count of its length
Return the result as a map

edited Mar 20, 2019 at 1:05

answered Sep 30, 2018 at 14:42

Adam Millerchip

23.3k6 gold badges62 silver badges86 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Badu · Accepted Answer · 2018-09-30 14:41:14Z

2

Use Enum.reduce

  def count(sentence) do
    sentence
    |> String.split() 
    |> Enum.reduce(%{}, fn word, sentence_map -> 
        Map.update(sentence_map, word, 1, fn existing_count -> existing_count+1
        end) 
     end)
   end

answered Sep 30, 2018 at 14:41

Badu

1,0828 silver badges8 bronze badges

Collectives™ on Stack Overflow

Elixir convert string to map code not working

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related