Question 409416 in Flutter Question posted in
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how to get values from map based on condition in flutter dart?

Using map.entries property i want to fetch all values those are even in a map data,

I have any other solutions to get this output but i want it to solve it with map.entries property…

its return null when value is not even

output should be [2,4] instead of [null,2,null,4] 

void main() {
  final  myMap={
    'first':1,
    'second':2,
    'three':3,
    'four':4,
  };

  List<dynamic> list=[];

  list=myMap.entries.map((e) {
    if(e.value%2==0)
    return e.value;
    
  }).toList();
  print(list);



}
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2

Answers


  1. 0

    Try below code and try to use where condition/method to filter out null values

    void main() {
  final myMap = {
    'first': 1,
    'second': 2,
    'three': 3,
    'four': 4,
  };

 
  List<dynamic> list = myMap.entries
      .map((e) => e.value % 2 == 0 ? e.value : null)
      .where((value) => value != null)
      .toList();

  print(list); 
}

    Read where method

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  2. 0

    Is there a reason why you specifically want to use entries? Surely using values seems better. Then you can do

    list = myMap.values.where((e) => e % 2 == 0).toList()

    If you insist on entries then do it like

    list = myMap.entries.where((e) => e.value % 2 == 0).map((e) => e.value).toList()
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