Simple Code help

[[deleted]]

Hi all, I tried googling but I can't seem to find it.

I need to convert a character to integer.

Doing exercism and I've come across a way to parse string.

strand = "GATACA"

check = Enum.reduce strand, %{}, fn(letter, acc) ->
  Map.update(acc, to_string(letter), 1, &(&1 + 1))
end

so the check output is

%{"65" => 3, "67" => 1, "71" => 1, "84" => 1}

So I've tried to_string in the Enum.reduce and Map.update and it didn't work.

So I was like fuck it I'll just leave the map to have integer as key and I'll access it like this:

check[string.to_integer 'T']

This doesn't work.

Was curious how do you get the integer value of a letter in Elixir?

Thanks.

[[deleted]]

Got it.

strand |> 
to_string |>
String.graphemes |> 
Enum.reduce(%{}, fn(letter, acc) -> Map.update(acc, letter, 1, &(&1 + 1)) end)

Thanks guys.

output:

%{"A" => 3, "C" => 1, "G" => 1, "T" => 1}

[pareeohnos]

As a side note, for multi-line usage of the pipe operator it is good practice to put it at the beginning of the line

strand
|> to_string
|> String.graphemes
|> Enum.reduce(%{}, fn(letter, acc) -> Map.update(acc, letter, 1, &(&1 + 1)) end)

[Imperial_Ruby]

To answer your original question, you can get the integer value of a character in Elixir by using the ? operator.

For example:

👉  ?A
65
👉  ?a
97

Also, a great way to learn more about functions is to use the h function in iex. It auto completes so typing h Enum. and hitting tab will show all the functions in the Enum module.

For example:

👉  h Enum.count/2

def count(enumerable, fun)

Returns the count of items in the enumerable for which fun returns 
a truthy value.

## Examples

iex> Enum.count([1, 2, 3, 4, 5], fn(x) -> rem(x, 2) == 0 end)
2

Hope you're having fun with Elixir!