Using associative arrays

How to:

Creating a Map is straightforward. You use the %{} syntax, like so:

my_map = %{"name" => "Alex", "age" => 32}

Accessing values is done by using the keys:

IO.puts my_map["name"]

Output: Alex

To add or update values, you can use the Map.put/3 function:

updated_map = Map.put(my_map, "location", "NY")

Output: %{"age" => 32, "location" => "NY", "name" => "Alex"}

Removing keys is just as simple with Map.delete/2:

trimmed_map = Map.delete(updated_map, "age")

Output: %{"location" => "NY", "name" => "Alex"}

Deep Dive

Maps in Elixir are an evolution of the older key-value storage types, like Hashes in Ruby or Dictionaries in Python. They allow for more efficient lookups and insertions, making them a go-to for modern Elixir programming. It’s worth noting that before Maps, Elixir used HashDict and Dict modules, which are deprecated now.

However, for scenarios requiring ordered data, you might look at keyword lists in Elixir. These are lists of tuples, efficient for smaller collections but not as performance-friendly for large datasets as Maps.

Keep in mind that Maps store their keys in a “flat” structure, making direct access to nested values a bit tricky. For deep nesting, you might consider structured access via the get_in, put_in, update_in, and get_and_update_in functions, which allow for a more dynamic approach to nested data manipulation.

In sum, while Maps are your go-to for associative array needs in Elixir, the language offers a rich variety of data structures for every scenario, encouraging you to pick the right tool for the job.