Add Key for list of multiple object ~ dart

Question

   final uri = Uri.parse(
        "https://api.binance.com/api/v3/klines?symbol=BTCUSDT&interval=1h");
    final res = await http.get(uri);
    var data = (jsonDecode(res.body)).toList();



    var name = [
      "Datetime",
      "Open",
      "High",
      "Low",
      "Close",
      "Volume",
      "Close time",
      "Quote",
      "Number of trades",
      "taker buy",
      "taker buy quote",
      "ignore"
    ];

    var output = [
      for (var d in data) Map<String, String>.fromIterable(name,value: d)
    ];
    print(output);

Try:

var output = Map<String, dynamic>.fromIterables(name, data);

Error: Uncaught Error: Invalid argument(s): Iterables do not have same length.

Error 2: Unhandled Exception: type 'List' is not a subtype of type '((dynamic) => String)?'

Need output like below list:

   [ {Open time: 1650409200000, Open: 41395.38000000, High: 41539.90000000, Low: 41395.38000000, Close: 41493.18000000, Volume: 850.49595000, Close time: 1650412799999, Quote asset volume: 35269640.77746520, Number of trades: 22594, Taker buy base asset volume: 396.50601000, Taker buy quote asset volume: 16441271.67871090, Ignore: 0},
    {Open time: 1650412800000, Open: 41493.19000000, High: 41541.23000000, Low: 41250.26000000, Close: 41295.37000000, Volume: 1226.31947000, Close time: 1650416399999, Quote asset volume: 50763275.81698850, Number of trades: 35252, Taker buy base asset volume: 508.56187000, Taker buy quote asset volume: 21051672.90479120, Ignore: 0}]

i'am using for method for each object but it dose not return the list value.

var output = [Map.fromIterables(name, data[0]), Map.fromIterables(name, data[1])];. More generally: var output = [for (var d in data) Map.fromIterables(name, d)];. — jamesdlin
– jamesdlin, Commented May 10, 2022 at 22:21
Hi @jamesdlin This one work for sample given 2 datas but i have 500 data like this it's not working for this.... Data source : api.binance.com/api/v3/klines?symbol=BTCUSDT&interval=1h — Buddy Ramesh
– Buddy Ramesh, Commented May 11, 2022 at 19:54
It should work regardless of the number of entries in data as long as each entry has the same length as name. If it's not working (what error?), then that one of your entries is malformed. — jamesdlin
– jamesdlin, Commented May 11, 2022 at 20:23
i'm sure about all the entries in data same length. but get below error ERROR: Unhandled Exception: type 'List<dynamic>' is not a subtype of type '((dynamic) => String)?' — Buddy Ramesh
– Buddy Ramesh, Commented May 11, 2022 at 21:05

GiuseppeFn · Accepted Answer · 2022-05-12 21:45:45Z

1

You probably didn't notice that what you're doing is wrong

Map.fromIterables takes two lists (In your case, a String list and a dynamic list), and makes the first list's values the map's keys, and the second list's values the map's values.

But what you're saying to dart by

 Map<String, dynamic>.fromIterables(name, data);

Is actually: "Hey I have a String list, and a list with two lists, could you make it a Map please?"

So more simply, do the following:

//You make a list out of data[0] and data[1]
var output = [Map<String, dynamic>.fromIterables(name, data[0]), Map<String, dynamic>.fromIterables(name, data[1])];

Or, if data's length is variable you could use:

var output = [for(var d in data) Map<String, dynamic>.fromIterables(name, d)];
//For each element in data you parse the data

edited May 12, 2022 at 21:45

answered May 10, 2022 at 22:43

GiuseppeFn

4253 silver badges8 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Buddy Ramesh Over a year ago

Hi, This one work for sample given 2 datas but i have 500 data like this it's not working for this.... Data source : api.binance.com/api/v3/klines?symbol=BTCUSDT&interval=1h

GiuseppeFn Over a year ago

As I said in the answer, if you have more than 2 entries, you have to use the second solution :)

Collectives™ on Stack Overflow

Add Key for list of multiple object ~ dart

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related