associateWith<V> method

Map<T, V> associateWith<V>(
  1. V valueSelector(
    1. T value
    )
)

Returns a Map containing the elements paired with the value from valueSelector.

If the source list contains duplicated keys, only one of them will be left on the map.

The iteration order of the list is preserved.

final charCodes = [72, 69, 76, 76, 79]; // second 76 is ignored
final fromCharCode = charCodes.associateWith(
  (code) => String.fromCharCode(code),
);

print(fromCharCode); // {72: 'H', 69: 'E', 76: 'L', 79: 'O'}

class Person {
  const Person(this.firstName, this.lastName);

  final String firstName;

  final String lastName;

  @override
  String toString() => '$firstName $lastName';
}

final scientists = [
  Person('Grace', 'Hopper'),
  Person('Jacob', 'Bernoulli'),
  Person('Johann', 'Bernoulli'),
];

final byName = scientists.associateWith((value) => value.lastName);

print(byName); // {Grace Hopper: Hopper, Jacob Bernoulli: Bernoulli, Johann Bernoulli: Bernoulli}

Implementation

Map<T, V> associateWith<V>(V Function(T value) valueSelector) {
  return associate((key) => Pair(key, valueSelector(key)));
}