Dart .addAll()

In Dart, the .addAll() method adds all key-value pairs from another Map into an existing Map. This is commonly used when merging maps or inserting multiple entries at once.

If a key from the source map already exists in the target map, its value will be replaced by the value from the source map.

Syntax

mapVariable.addAll(otherMap)

mapVariable is the Map object to which new key–value pairs will be added.

Parameters:

• otherMap: A map whose key–value pairs are added to mapVariable. If a key already exists, its value is overwritten.

Return value:

This method returns void. The original map is modified in place.

Example

The following example demonstrates how .addAll() can be used to merge two maps:

void main() {
  Map<String, int> inventory = {
    'Apples': 5,
    'Bananas': 3
  };

  Map<String, int> newItems = {
    'Oranges': 4,
    'Grapes': 10
  };

  inventory.addAll(newItems);

  print(inventory);
}

Copy to clipboard
Copy to clipboard

The output of this code is as follows:

{Apples: 5, Bananas: 3, Oranges: 4, Grapes: 10}

Copy to clipboard
Copy to clipboard