Functional Class Homework

school.exs

school = [
  %{
    name: "1A",
    teacher: %{
      age: 28,
      first_name: "Tricia",
      last_name: "Garrett"
    },
    assistants: %{
      age: 38,
      first_name: "Liliana",
      last_name: "Kidd"
    },
    students: [
      %{
        age: 46,
        first_name: "Luz",
        last_name: "Casey"
      },
      %{
        age: 38,
        first_name: "Rosemary",
        last_name: "Barber"
      }
    ]
  },
  %{
    name: "1B",
    teacher: %{
      age: 43,
      first_name: "Ollie",
      last_name: "Matthews"
    },
    assistants: nil,
    students: [
      %{
        age: 45,
        first_name: "Ollie",
        last_name: "Sandoval"
      },
      %{
        age: 27,
        first_name: "Gale",
        last_name: "Coleman"
      }
    ]
  },
  %{
    name: "2A",
    teacher: %{
      age: 49,
      first_name: "Liza",
      last_name: "Vega"
    },
    assistants: %{
      age: 48,
      first_name: "Tricia",
      last_name: "Brewer"
    },
    students: [
      %{
        age: 24,
        first_name: "Ophelia",
        last_name: "Roy"
      },
      %{
        age: 40,
        first_name: "Ophelia",
        last_name: "Sears"
      },
      %{
        age: 37,
        first_name: "Gale",
        last_name: "Strong"
      }
    ]
  },
  %{
    name: "2B",
    teacher: %{
      age: 24,
      first_name: "Rochelle",
      last_name: "Wilcox"
    },
    assistants: [
      %{
        age: 32,
        first_name: "Gale",
        last_name: "Christensen"
      },
      %{
        age: 46,
        first_name: "Luz",
        last_name: "Crawford"
      },
      %{
        age: 38,
        first_name: "Rosemary",
        last_name: "Casey"
      }
    ],
    students: [
      %{
        age: 42,
        first_name: "Gale",
        last_name: "Joseph"
      },
      %{
        age: 38,
        first_name: "Ophelia",
        last_name: "Crawford"
      },
      %{
        age: 45,
        first_name: "Gale",
        last_name: "Bowers"
      }
    ]
  }
]


school
|> Enum.flat_map(fn x -> x end)
|> Enum.filter(fn {type, _} -> Enum.member?([:students, :teacher, :assistants], type) end)
|> Enum.map(fn {type, items} -> %{(if type == :students, do: :students, else: :staffs) => List.wrap(items)} end)
|> Enum.reduce(fn x, acc -> Map.merge(x, acc, fn _, x, y -> Enum.concat(x, y) end) end)
|> Enum.map(fn {key, value } -> { key, Enum.filter(value, fn %{ age: age } -> age >= 30 end)} end)
|> Enum.map(fn {key, value } -> { key, Enum.group_by(value, fn %{first_name: first_name} -> first_name end, fn %{first_name: first_name, last_name: last_name} -> "#{first_name} #{last_name}" end)} end)
|> Map.new
|> IO.inspect