Elixir is sorting map by key name in ascending order, but I don’t want this behaviour. It is causing me to have undesired reports output. I’d like to have the employee number and names to begin, then followed by leave types instead of the following. [image] Is there a way to rearrange the map by…

Thank you all for jumping on this issue. I truly appreciate. I had to write a Report module that: Aceepts a list of records, and a list of keys in order I want. Loops throuch each record and map it with Map.get(record, ordered_key, "") records = [ %{ "Annual Leave" => Decimal.new("21…

If you need sorted keys then a Map is the wrong data structure. There are lists, keyword lists, records, custom data structures, etc. Search for “map with ordered keys” as this has been discussed on here a few times.

Have you considered using structs with a custom inspection protocol implementation? Maps with string keys deep into the program always smell.

[image] kamaroly: Elixir is sorting map by key name in ascending order, but I don’t want this behaviour. Maps are an unordered dataformat. The BEAM just has a default sort order given it has a global ordering between any term it can represent, which is used to order things where they need to …

I haven’t tried this. It looks like I just need to use lists.

It’s not entirely a view issue. I have a pivot table module I pass any list of map and specify what should be rows, colum to transpose and colum to use as value for sum, count etc… then I render it as html, csv, pdf etc… to download or render in a browser. I will try with lists and see how it works…

[image] kamaroly: then I render it as html, csv, pdf etc… Sounds like presentation layer…

I always seem to struggle with choosing the right data structure for modeling data. My (probably naive) way of thinking about it that maps are for data that will need fast insert, fast retrieval, and fast updates but for which order is not (as) important. Lists (including keyword lists) are for thin…

[image] kamaroly: So far it looks like a list of tuples maintains the order. Historical trivia: back before maps were introduced into Erlang, Elixir had a module named ListDict which managed the data structure you describe – an ordered list of two element tuples that could be treated like a m…

To make matters worse (? :grinning:) the ordering of elements in maps is completely undefined and changes depending on the number of elements. It use to be that for less than 32 elements the ordering was term ordering and for more elements it was “random” depending on the internal search algorithm u…

Convert to a list of tuples, then sort using a comparator function map |> Map.to_list() |> |> Enum.sort_by(fn {key, _value} -> key end)

How to Control Map Key Order in Elixir for Custom Report Formatting?

Questions & Help Questions

NobbZ December 27, 2024, 5:17pm 7

Sounds like presentation layer…