Hello.
Trying to solve this problem I wrote the following algorithm:

string = "3340c9571y40m47ku49t9315mrvzqo667k36e"

# %{
#  "c" => 1,
#  "e" => 1,
#  "k" => 2,
#  "m" => 2,
#  "o" => 1,
#  "q" => 1,
#  "r" => 1,
#  "t" => 1,
#  "u" => 1,
#  "v" => 1,
#  "y" => 1,
#  "z" => 1
#  }
#  [1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1]
# Expected result => 14

def is_numeric?(char) do
    Regex.match?(~r/^\d+$/, char)
end

def total_non_numeric_chars(string) do
    String.codepoints(string)
    |> Enum.reduce(%{}, fn char, acc ->
      cond do
        !is_numeric?(char) ->
          if Map.has_key?(acc, char),
            do: Map.update!(acc, char, &(&1 + 1)),
            else: Map.put(acc, char, 1)

        true ->
          acc
      end
    end)
    |> Map.values()
    |> Enum.sum()
end

I would like to know if is possible to avoid the nested cond and if with some patter matching or other technique.
Any suggestions to improve the algorithm is welcome.

Thanks.