> For the complete documentation index, see [llms.txt](https://elixir.petrolidas.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://elixir.petrolidas.com/exhort/day-14.md).
# Day 14
## Exercises
* [x] [Boutique Inventory](#boutique-inventory)
### Boutique Inventory
[Boutique Inventory in Elixir on Exercism](https://exercism.org/tracks/elixir/exercises/boutique-inventory) **|** [View my solution](https://exercism.org/tracks/elixir/exercises/boutique-inventory/solutions/petros)
#### Solution
Expand to see code (spoiler alert)
{% code lineNumbers="true" %}
```elixir
defmodule BoutiqueInventory do
def sort_by_price(inventory) do
inventory
|> Enum.sort_by(&(&1.price))
end
def with_missing_price(inventory) do
inventory
|> Enum.filter(&is_nil(&1.price))
end
def update_names(inventory, old_word, new_word) do
inventory
|> Enum.map(&replace_word(&1, old_word, new_word))
end
defp replace_word(map, old_word, new_word) do
name = String.replace(map.name, old_word, new_word)
Map.put(map, :name, name)
end
def increase_quantity(item, count) do
qbs = Map.new(item.quantity_by_size, fn {k, v} -> {k, v + count} end)
%{item | quantity_by_size: qbs }
end
def total_quantity(item) do
item.quantity_by_size
|> Enum.reduce(0, fn {_, v}, sum -> sum + v end)
end
end
```
{% endcode %}
[View gist on GitHub](https://gist.github.com/petros/809098bdb9b12a6b3def38b291e7f05e)
#### Notes
Oh Zeus. I really struggled with this one. And it was so simple. I don't know why. Here's my accepted solution:
```elixir
def increase_quantity(item, count) do
qbs = Map.new(item.quantity_by_size, fn {k, v} -> {k, v + count} end)
%{item | quantity_by_size: qbs }
end
```
I was trying all sorts of irrelevant things :grimacing:. I was also thrown off by the mention of `Enum.into` in `README.md`. I guess it was an alternative to `Map.new`?\
\
For `total_quantity/1`, I used a different approach, while the exercise recommended `Enum.reduce`. It was the purpose of the exercise to teach you that. My initial implementation was:
```elixir
item.quantity_by_size
|> Map.values
|> Enum.sum
```
I think it's a little easier in the eyes, but I have no idea if it's slower as I am calling a `Map` function and then an `Enum` function. Whereas `reduce/3` is one function.
## Overall progress