ProgramGuruTo set a default value for a key in a map in Dart, you can use the putIfAbsent method.
We can set a default value for a key in a map in Dart using the putIfAbsent method, which inserts a key-value pair if the key does not already exist in the map.
For example,
myMap with some key-value pairs. In this example, the map has string keys and integer values.putIfAbsent method to set a default value for a key. The putIfAbsent method takes the key and a function that returns the default value to be inserted if the key is not already present in the map.print function.void main() {
// Declare and initialize a map
Map<String, int> myMap = {
'one': 1,
'two': 2,
'three': 3
};
// Set a default value using putIfAbsent method
myMap.putIfAbsent('four', () => 4);
// Print the updated map
print(myMap);
}{one: 1, two: 2, three: 3, four: 4}We can set a default value for a key in a map in Dart using the putIfAbsent method, which inserts a key-value pair if the key does not already exist in the map, based on a condition.
For example,
myMap with some key-value pairs. In this example, the map has string keys and integer values.putIfAbsent method to set a default value for a key based on a condition. The putIfAbsent method takes the key and a function that returns the default value to be inserted if the key is not already present in the map.print function.void main() {
// Declare and initialize a map
Map<String, int> myMap = {
'one': 1,
'two': 2,
'three': 3
};
// Set a default value conditionally using putIfAbsent method
myMap.putIfAbsent('four', () => myMap['four'] ?? 4);
// Print the updated map
print(myMap);
}{one: 1, two: 2, three: 3, four: 4}We can set multiple default values for keys in a map in Dart using the putIfAbsent method, which inserts key-value pairs if the keys do not already exist in the map.
For example,
myMap with some key-value pairs. In this example, the map has string keys and integer values.putIfAbsent method to set multiple default values for keys. The putIfAbsent method takes the key and a function that returns the default value to be inserted if the key is not already present in the map.print function.void main() {
// Declare and initialize a map
Map<String, int> myMap = {
'one': 1,
'two': 2,
'three': 3
};
// Set multiple default values using putIfAbsent method
myMap.putIfAbsent('four', () => 4);
myMap.putIfAbsent('five', () => 5);
// Print the updated map
print(myMap);
}{one: 1, two: 2, three: 3, four: 4, five: 5}In this tutorial, we learned How to Set a Default Value for a Key in a Map in Dart language with well detailed examples.