description

# HashSet<E>.from constructor

HashSet<E>.from(

1. Iterable elements

)

Create a hash set containing all `elements`.

Creates a hash set as by `HashSet<E>()` and adds all given `elements` to the set. The elements are added in order. If `elements` contains two entries that are equal, but not identical, then the first one is the one in the resulting set.

All the `elements` should be instances of `E`. The `elements` iterable itself may have any element type, so this constructor can be used to down-cast a `Set`, for example as:

    Set<SuperType> superSet = ...;
    Set<SubType> subSet =
        HashSet<SubType>.from(superSet.whereType<SubType>());

Example:

    final numbers = <num>[10, 20, 30];
    final hashSetFrom = HashSet<int>.from(numbers);
    print(hashSetFrom); // fx {20, 10, 30}

## Implementation

    factory HashSet.from(Iterable<dynamic> elements) {
      HashSet<E> result = HashSet<E>();
      for (final e in elements) {
        result.add(e as E);
      }
      return result;
    }