Elixir

Other Elixir solutions.

defmodule BoutiqueInventory do
  def sort_by_price(inventory) do
    Enum.sort_by(inventory, fn row -> row[:price] end)
  end

  def with_missing_price(inventory) do
    Enum.filter(inventory, fn row -> !row[:price] end)
  end

  def update_names(inventory, old_word, new_word) do
    Enum.map(inventory, fn row ->
      %{row | name: String.replace(row.name, old_word, new_word)}
    end)
  end

  def increase_quantity(item, count) do
    new_quantities = Map.new(item.quantity_by_size, fn {k, v} -> {k, v + count} end)

    %{item | quantity_by_size: new_quantities}
  end

  def total_quantity(item) do
    Enum.reduce(
      item.quantity_by_size,
      0,
      fn {_, x}, acc -> acc + x end
    )
  end
end