Dart Runes reduce()
Syntax & Examples

Runes.reduce() method

The `reduce` method in Dart reduces a collection to a single value by iteratively combining elements of the collection using the provided function.

Syntax of Runes.reduce()

The syntax of Runes.reduce() method is:

 int reduce(int combine(int value int element))

This reduce() method of Runes reduces a collection to a single value by iteratively combining elements of the collection using the provided function.

Parameters

ParameterOptional/RequiredDescription
combinerequiredA function that takes an integer value and an integer element, and returns the new combined value.

Return Type

Runes.reduce() returns value of type int.


✐ Examples

1 Reducing a list of numbers to calculate the sum

In this example,

  1. We create a list numbers containing integers.
  2. We use the reduce() method with a function that adds each element to the accumulated value.
  3. We print the final sum obtained by reducing the list.

Dart Program

void main() {
  List<int> numbers = [1, 2, 3, 4, 5];
  int sum = numbers.reduce((value, element) => value + element);
  print(sum);
}

Output

15

2 Reducing a list of strings to concatenate them

In this example,

  1. We create a list words containing strings.
  2. We use the reduce() method with a function that concatenates each word to the accumulated value with a space.
  3. We print the final concatenated string obtained by reducing the list.

Dart Program

void main() {
  List<String> words = ['hello', 'world'];
  String combined = words.reduce((value, word) => value + ' ' + word);
  print(combined);
}

Output

hello world

3 Reducing a set of numbers to calculate the product

In this example,

  1. We create a set uniqueNumbers containing integers.
  2. We use the reduce() method with a function that multiplies each element to the accumulated value.
  3. We print the final product obtained by reducing the set.

Dart Program

void main() {
  Set<int> uniqueNumbers = {1, 2, 3};
  int product = uniqueNumbers.reduce((value, number) => value * number);
  print(product);
}

Output

6

Summary

In this Dart tutorial, we learned about reduce() method of Runes: the syntax and few working examples with output and detailed explanation for each example.