Convert map into a list in dart

Question

I am trying to convert a map into a list. I'm trying to use the forEach() method.But i don't know where i'm going wrong.Can someone help? Also after converting them to lists,i want to access their index.How to do?

For eg: I have 2 maps

Map foodMap = {
     value:50
     title:'food',
}

Map travelMap={
     value:30,
     title:'travel'
}

List<String> sampleList = [];

I want to convert my two maps into list and add them into sampleList.

https://api.flutter.dev/flutter/dart-core/Map-class.html#instance-properties — pskink, Dec 18 '19 at 18:16
How do you want to add them? Maps and lists are structured differently, so you cannot just "convert" them. Can you precisely explain what you expect to have in the end? — creativecreatorormaybenot, Dec 18 '19 at 18:25
I want to convert those two maps into a list and merge them into one list and then want to access each element's index in that list. — Aishwarya, Dec 18 '19 at 18:32
so read [Iterable](https://api.flutter.dev/flutter/dart-core/Map-class.html) official documentation - it has methods for merging two `Iterable`s and converting to a list — pskink, Dec 18 '19 at 18:33
I'm not able to understand it. Can you try and share the code? — Aishwarya, Dec 18 '19 at 18:37
`var iterable1 = Iterable.generate(3, (i) => i); var iterable2 = Iterable.generate(3, (i) => 10 * i); var iterable3 = iterable1.followedBy(iterable2).toList(); print(iterable3);` — pskink, Dec 18 '19 at 18:38
Does this answer your question? [How to convert a Map to List in Java?](https://stackoverflow.com/questions/1026723/how-to-convert-a-map-to-list-in-java) — Jay Mungara, Dec 18 '19 at 18:40
or even: `var iterable3 = iterable1.toList() + iterable2.toList();` — pskink, Dec 18 '19 at 18:52
I think, what you want is to merge list of json data to single map. like `{"food" : 50, "travel": 30}` — Crazy Lazy Cat, Dec 18 '19 at 19:10

score 0 · Answer 1 · answered Dec 18 '19 at 19:47

Map foodMap = {
  "value": 50,
  "title": 'food',
};

Map travelMap = {
  "value": 30,
  "title": 'travel',
};

Map<String, double> sampleList = {};

I think, this is how you want to add two maps:

void _addToMappedList(Map<String, double> sampleList, Map newData) {
  String title = newData["title"];
  double value = double.tryParse(newData["value"].toString());

  sampleList[title] = value;
}

....

_addToMappedList(sampleList, foodMap);
_addToMappedList(sampleList, travelMap);

To merge list of maps to single

List<Map> mapList = [/*Contains list of maps*/];
....
mapList.forEach((mapItem) => _addToMappedList(sampleList, travelMap))

To access their index

print(sampleList.entries.elementAt(1));

Convert map into a list in dart

1 Answers1