SplayTreeMap.fromIterable constructor - SplayTreeMap - dart:collection library (original) (raw)

SplayTreeMap<K, V>.fromIterable(

1. Iterable iterable, {
2. K key(
   1. dynamic element
      )?,
3. V value(
   1. dynamic element
      )?,
4. int compare(
   1. K key1,
   2. K key2
      )?,
5. bool isValidKey(
   1. dynamic potentialKey
      )?, })

Creates a SplayTreeMap where the keys and values are computed from theiterable.

For each element of the iterable this constructor computes a key/value pair, by applying key and value respectively.

The keys of the key/value pairs do not need to be unique. The last occurrence of a key will simply overwrite any previous value.

If no functions are specified for key and value, the default is to use the iterable value itself. Example:

final numbers = [12, 11, 14, 13];
final mapFromIterable =
    SplayTreeMap<int, int>.fromIterable(numbers,
        key: (i) => i, value: (i) => i * i);
print(mapFromIterable); // {11: 121, 12: 144, 13: 169, 14: 196}

Implementation

factory SplayTreeMap.fromIterable(
  Iterable iterable, {
  K Function(dynamic element)? key,
  V Function(dynamic element)? value,
  int Function(K key1, K key2)? compare,
  bool Function(dynamic potentialKey)? isValidKey,
}) {
  SplayTreeMap<K, V> map = SplayTreeMap<K, V>(compare, isValidKey);
  MapBase._fillMapWithMappedIterable(map, iterable, key, value);
  return map;
}