(ArgumentError) argument error (stdlib 3.11.2) :maps.from_list

Questions / Help
, ,
1 
results = 
[
  {%{
     asset: "3QvxP6YFBKpWJSMAfYtL8Niv8KmmKsnpb9uQwQpg8QN2",
     price: 0.10878614,
     priced_in: "WAVES",
     value_in_usd_n: 0.11197357390200001
   },
   %{
     asset: "3QvxP6YFBKpWJSMAfYtL8Niv8KmmKsnpb9uQwQpg8QN2",
     price: 1.668e-5,
     priced_in: "8LQW8f7P5d5PZM7GtZEBgaqRPGSzS3DfPuiXrURJ4AJS",
     value_in_usd_n: 0.126019068
   }},
  {%{
     asset: "474jTeYx2r2Va35794tCScAXWJG9hU2HcgxzMowaZUnu",
     price: 0.0257055,
     priced_in: "8LQW8f7P5d5PZM7GtZEBgaqRPGSzS3DfPuiXrURJ4AJS",
     value_in_usd_n: 194.20762305
   },
   %{
     asset: "474jTeYx2r2Va35794tCScAXWJG9hU2HcgxzMowaZUnu",
     price: 191.02,
     priced_in: "WAVES",
     value_in_usd_n: 196.61688600000002
   }},
  {%{
     asset: "4LHHvYGNKJUg5hj65aGD5vgScvCBmLpdRFtjokvCjSL8",
     price: 0.078461,
     priced_in: "DG2xFkPdDwKUoBkzGAhQtLpSGzfXLiCYPEzeKH2Ad24p",
     value_in_usd_n: 0.078461
   },
   %{
     asset: "4LHHvYGNKJUg5hj65aGD5vgScvCBmLpdRFtjokvCjSL8",
     price: 0.07653975,
     priced_in: "WAVES",
     value_in_usd_n: 0.07878236467500001
   }}
]

Code:

results
	|> Map.new(fn {%{
		asset: asset,
		price: ask,
		priced_in: buy_with,
		value_in_usd_n: purchase_value_in_usd_n
		},
		%{
			asset: asset,
			price: bid,
			priced_in: sell_into,
			value_in_usd_n: sell_value_in_usd_n
			}}
			->
				%{
					asset: asset,
					buy_with: buy_with,
					ask: ask,
					purchase_value_in_usd_n: purchase_value_in_usd_n, 
					sell_into: sell_into,
					bid: bid,
					sell_value_in_usd_n: sell_value_in_usd_n,
					profit_percentage: ((sell_value_in_usd_n - purchase_value_in_usd_n) / purchase_value_in_usd_n) * 100 |>Float.round(2)
		}
	end)

Error:

** (ArgumentError) argument error
    (stdlib 3.11.2) :maps.from_list([%{ask: 0.10878614, asset: "3QvxP6YFBKpWJSMAfYtL8Niv8KmmKsnpb9uQwQpg8QN2", bid: 1.654e-5, buy_with: "WAVES", profit_percentage: 11.6, purchase_value_in_usd_n: 0.11197357390200001, sell_into: "8LQW8f7P5d5PZM7GtZEBgaqRPGSzS3DfPuiXrURJ4AJS", sell_value_in_usd_n: 0.12496135400000001}, %{ask: 0.0257055, asset: "474jTeYx2r2Va35794tCScAXWJG9hU2HcgxzMowaZUnu", bid: 191.02, buy_with: "8LQW8f7P5d5PZM7GtZEBgaqRPGSzS3DfPuiXrURJ4AJS", profit_percentage: 1.24, purchase_value_in_usd_n: 194.20762305, sell_into: "WAVES", sell_value_in_usd_n: 196.61688600000002}, %{ask: 0.078461, asset: "4LHHvYGNKJUg5hj65aGD5vgScvCBmLpdRFtjokvCjSL8", bid: 0.07653975, buy_with: "DG2xFkPdDwKUoBkzGAhQtLpSGzfXLiCYPEzeKH2Ad24p", profit_percentage: 0.41, purchase_value_in_usd_n: 0.078461, sell_into: "WAVES", sell_value_in_usd_n: 0.07878236467500001}
    (elixir 1.10.1) lib/map.ex:213: Map.new_transform/3

What did I miss? Thanks so much for your patient help! :slight_smile:

2

The function passed to Map.new/2 is specced to have this type:

term -> {key, value}

The function in your example is returning a map instead of a two-element tuple.

Based on the code in the function, I believe you want Enum.map/2, not Map.new/2.

1 Like
3

Got it! Thanks for helping me make sense of it.