Remove fields from nested struct

Questions / Help
,
1

I have this struct of preload records.
I want to remove
__meta__ and Ecto.Association.NotLoaded from the main struct as well as from the nested array of preloaded records. To make it a simple map

  %Facility{
  __meta__: #Ecto.Schema.Metadata<:loaded, "facilities">,
  id: 4875,
  instance: #Ecto.Association.NotLoaded<association :instance is not loaded>,
  name: "Facility",
 units: [
%Unit{
  __meta__: #Ecto.Schema.Metadata<:loaded, "units">,
  facility: #Ecto.Association.NotLoaded<association :facility is not loaded>,
  facility_id: 4875,
  id: 1593,
  name: "Storage",
  rooms: #Ecto.Association.NotLoaded<association :rooms is not loaded>
},
%Unit{
  __meta__: #Ecto.Schema.Metadata<:loaded, "units">,
  cdc_location_class_id: nil,
  facility: #Ecto.Association.NotLoaded<association :facility is not loaded>,
  facility_id: 4875,
  id: 1594,
  name: "Storage unit",
  rooms: #Ecto.Association.NotLoaded<association :rooms is not loaded>
}
],
users: #Ecto.Association.NotLoaded<association :users is not loaded>
}

Is it possible?

Thanks

2

Is it possible?

Yes, try writing a recursive function.

1 Like
3

Everything is about transforming data… Another way is to use Enum and Map modules :slight_smile:

iex> h Enum.
EmptyError           OutOfBoundsError     all?/1               
all?/2               any?/1               any?/2               
at/2                 at/3                 chunk_by/2           
chunk_every/2        chunk_every/3        chunk_every/4        
chunk_while/4        concat/1             concat/2             
count/1              count/2              dedup/1              
dedup_by/2           drop/2               drop_every/2         
drop_while/2         each/2               empty?/1             
fetch!/2             fetch/2              filter/2             
find/2               find/3               find_index/2         
find_value/2         find_value/3         flat_map/2           
flat_map_reduce/3    group_by/2           group_by/3           
intersperse/2        into/2               into/3               
join/1               join/2               map/2                
map_every/3          map_join/2           map_join/3           
map_reduce/3         max/1                max/2                
max_by/2             max_by/3             member?/2            
min/1                min/2                min_by/2             
min_by/3             min_max/1            min_max/2            
min_max_by/2         min_max_by/3         random/1             
reduce/2             reduce/3             reduce_while/3       
reject/2             reverse/1            reverse/2            
reverse_slice/3      scan/2               scan/3               
shuffle/1            slice/2              slice/3              
sort/1               sort/2               sort_by/2            
sort_by/3            split/2              split_while/2        
split_with/2         sum/1                take/2               
take_every/2         take_random/2        take_while/2         
to_list/1            uniq/1               uniq_by/2            
unzip/1              with_index/1         with_index/2         
zip/1                zip/2

And Map

iex> h Map.       
delete/2             drop/2               equal?/2             
fetch!/2             fetch/2              from_struct/1        
get/2                get/3                get_and_update!/3    
get_and_update/3     get_lazy/3           has_key?/2           
keys/1               merge/2              merge/3              
new/0                new/1                new/2                
pop/2                pop/3                pop_lazy/3           
put/3                put_new/3            put_new_lazy/3       
replace!/3           split/2              take/2               
to_list/1            update!/3            update/4             
values/1
4

hey thanks for your input. I have one question is it also possible to add list of maps to a map in a specific order:

Like these two:

                    params = %{name: "john wick"}
                    list_of_maps = [%{id: 1}, %{id: 2}, %{id: 3}]

            result = %{name: "john wick", some_key: list_of_maps}

When i try to add them the order is reversed. I know its off topic just curious :slightly_smiling_face:

Can you suggest alternate appraoch?
Thanks

5

Can you suggest alternate appraoch?

Add them in the reversed order? I’m not sure what you are doing, though. Where do the maps come from?

6

If i added them in the reverse order then it should be a list. i want it to be a map. Params come from the function. And I want it to manipulate it and add list of items in it like the example above…

7

This should not reverse anything, could you please be more specific about the problem?

8

Params
|> Map.put(:key, list_of_maps)
The output is

      %{ key: [%{id:1}, ....], name: "john wick"}

What I want is this:

      %{ name: "john wick", key: [%{id:1}, ....] }
9

These outputs are identical. Try comparing them with === if you are in doubt.

1 Like
10

There is no difference in both, those are equivalent from elixirs point of view.

Keys in a map are without any ordering guarantees.

1 Like
11

Thanks

12

Thank you