Dart – Reduce Elements of Set

To reduce elements of a Set to a single value, call reduce() method and pass the combine function as argument. combine is a function with two parameters, where the first parameter is used for accumulation/aggregation and the second parameter is each element from the Set.

Syntax

The syntax to call reduce() method on Set mySet with combine passed as argument is

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mySet.reduce(combine)

Examples

In the following program, we take a Set mySet, with some numbers, and reduce these numbers to their sum.

main.dart

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int sum(int s, int e) {
  return s + e;
}

void main() {
  Set<int> mySet = {1, 3, 6, 10, 13, 15, 20};
  var result = mySet.reduce(sum);
  print('Result : $result');
}

Output

Result : 68

Now, let us take the same Set as in the above example, but reduce the elements to their product.

main.dart

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int product(int s, int e) {
  return s * e;
}

void main() {
  Set<int> mySet = {1, 3, 6, 10, 13, 15, 20};
  var result = mySet.reduce(product);
  print('Result : $result');
}

Output

Result : 702000

Conclusion

In this Dart Tutorial, we learned how to reduce the elements of a Set to a single value, with examples.