indexed method

Iterable<Indexed<E>> indexed({ int start = 0, int step = 1, @Deprecated('Use `start` instead of `offset`') int? offset, })

Returns a iterable that combines the index and value of this Iterable.

By default the index is zero based, but an arbitrary offset can be provided.

For example, the following expression returns '1: a, 2: b':

['a', 'b'].indexed(start: 1)
  .map((each) => '${each.index}: ${each.value}')
  .join(', ');

Implementation

Iterable<Indexed<E>> indexed({
  int start = 0,
  int step = 1,
  @Deprecated('Use `start` instead of `offset`') int? offset,
}) sync* {
  var index = offset ?? start;
  for (final element in this) {
    yield Indexed<E>(index, element);
    index += step;
  }
}