Dart Map forEach()
Syntax & Examples

Syntax of Map.forEach()

The syntax of Map.forEach() method is:

 void forEach(void action(K key, V value))

This forEach() method of Map applies action to each key/value pair of the map.

Parameters

ParameterOptional/RequiredDescription
actionrequiredthe function to apply to each key/value pair

Return Type

Map.forEach() returns value of type void.


✐ Examples

1 Iterate over a map of strings and integers

In this example,

  1. We create a map named map1 with string keys and integer values.
  2. We use the forEach() method to iterate over each key/value pair in map1.
  3. For each pair, we print the key and value to standard output.

Dart Program

void main() {
  Map<String, int> map1 = {'one': 1, 'two': 2, 'three': 3};
  map1.forEach((key, value) {
    print('Key: $key, Value: $value');
  });
}

Output

Key: one, Value: 1
Key: two, Value: 2
Key: three, Value: 3

2 Iterate over a map of integers and strings

In this example,

  1. We create a map named map2 with integer keys and string values.
  2. We use the forEach() method to iterate over each key/value pair in map2.
  3. For each pair, we print the key and value to standard output.

Dart Program

void main() {
  Map<int, String> map2 = {1: 'one', 2: 'two', 3: 'three'};
  map2.forEach((key, value) {
    print('Key: $key, Value: $value');
  });
}

Output

Key: 1, Value: one
Key: 2, Value: two
Key: 3, Value: three

3 Iterate over a map of strings

In this example,

  1. We create a map named map3 with string keys and string values.
  2. We use the forEach() method to iterate over each key/value pair in map3.
  3. For each pair, we print the key and value to standard output.

Dart Program

void main() {
  Map<String, String> map3 = {'apple': 'red', 'banana': 'yellow', 'cherry': 'red'};
  map3.forEach((key, value) {
    print('Key: $key, Value: $value');
  });
}

Output

Key: apple, Value: red
Key: banana, Value: yellow
Key: cherry, Value: red

Summary

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