Question 225584 in Flutter Question posted in
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Flutter – Dart How to compare 2 List <double> with rounded values?

I welcome everyone. Can you please tell me how to compare 2 List, rounding the values, for example, to two decimal places?

We have

var list1 = [3425,5559394484, 2351,4392210480, -2384,4831199322];
var list2 = [3425,5559394472, 2351,4392210480, -2384,4831199122];

You need to compare the values of the lists, rounding them up to 2 decimal places. the result should

be
print(ListEquality().equals(list1, list2)) // true

What is the best way to implement comparison? Thanks to everyone who will respond.

Tags:

3

Answers


  1. 0

    Besides using answer below comment, you can do like this:

    bool checkEquals(List<double> list1, List<double> list2) {
  if (list1.length != list2.length) {
    return false;
  }

  for (int i = 0; i < list1.length; i++) {
    if (_roundToTwoDecimals(list1[i]) != _roundToTwoDecimals(list2[i])) {
      return false;
    }
  }

  return true;
}

double _roundToTwoDecimals(double value) {
  return double.parse(value.toStringAsFixed(2));
}


void main() {
  var list1 = [3425.5559394484, 2351.4392210480, -2384.4831199322];
  var list2 = [3425.5559394472, 2351.4392210480, -2384.4831199122];

  print(checkEquals(list1, list2));  // Output: true
}
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  2. 0

    You can try the below soln

    I make method for length & equality which return true or false

    void main() {
  var list1 = [3425.5559394484, 2351.4392210480, -2384.4831199322];
  var list2 = [3425.5559394472, 2351.4392210480, -2384.4831199122];

  print(checkEqAndLength(list1, list2));  // Output: true
}




bool checkEqAndLength(List<double> l1, List<double> l2) {
  if (l1.length != l2.length) {
    return false;
  }

  for (int i = 0; i < l1.length; i++) { 
    if(double.parse(l1[i].toStringAsFixed(2)) != double.parse(l2[i].toStringAsFixed(2))){
      return false;
    }
  }
  return true;
}
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  3. 0 
    import 'package:collection/collection.dart';

void main() {
  var list1 = [3425.5559394484, 2351.4392210480, -2384.4831199322];
  var list2 = [3425.5559394472, 2351.4392210480, -2384.4831199122];

  final doubleEquality = EqualityBy<double, double>(_roundDouble);
  print(ListEquality(doubleEquality).equals(list1, list2));
}

double _roundDouble(double value) {
  return (value * 100).roundToDouble() / 100;
}
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