I used a helper function for Enum.count that used a regex with String.split that returned true or false depending on the occurrence of the substring. Probably not optimal, but I’m still learning:
def day2 do
input = File.read!(Path.absname("lib/day_two_input.txt"))
|> String.split("\n", trim: true)
|> Enum.count(&(day2_helper(&1) == true))
end
defp day2_helper(s) do
split = String.split(s, ~r/-|:|\s/, trim: :ok)
letter = Enum.at(split, 2)
min = Enum.at(split, 0)
|> String.to_integer
max = Enum.at(split, 1)
|> String.to_integer
count = Enum.at(split, 3)
|> String.graphemes
|> Enum.count(&(&1 == letter))
if count >= min && count <= max do
true
else
false
end
end
