在 Stream 上使用时，Distinct() 似乎没有过滤掉相同的结果

Question

请看一下这段代码=>

void main() async {
  Stream<int> _intStream() async* {
    for (int i = 0; i < 10; i++) yield i;
  }

  Stream<int> _even() => _intStream().where((int i) => i % 2 == 0);
  Stream<bool> _isEven(Stream<int> stream) => stream.map((int i) => i % 2 == 0);

  print('test 1: should print 5 [true] and 5 [false] alternate');
  await for (bool b in _isEven(_intStream())) {
    print('test 1: $b');
  }

  print('test 2: should print 5 [true]');
  await for (bool b in _isEven(_even())) {
    print('test 2: $b');
  }

  print('test 3: should print ONLY ONE [true]');
  await for (bool b in _isEven(_even().distinct())) {
    print('test 3: $b');
  }
}

我是不是用错了distinct()？

提前致谢

Answer 1

没关系，我只是把 distinct 放在了错误的地方，以下按预期工作

void main() async {
  Stream<int> _intStream() async* {
    for (int i = 0; i < 10; i++) yield i;
  }

  Stream<int> _even() => _intStream().where((int i) => i % 2 == 0);
  Stream<bool> _isEven(Stream<int> stream) => stream.map((int i) => i % 2 == 0);

  print('test 1: should print 5 [true] and 5 [false] alternate');
  await for (bool b in _isEven(_intStream())) {
    print('test 1: $b');
  }

  print('test 2: should print 5 [true]');
  await for (bool b in _isEven(_even())) {
    print('test 2: $b');
  }

  print('test 3: should print ONLY ONE [true]');
  await for (bool b in _isEven(_even()).distinct()) {
    print('test 3: $b');
  }
}

在 Stream 上使用时，Distinct() 似乎没有过滤掉相同的结果

Distinct() doesn't seem to filter out identical results when used on a Stream

flutter

asynchronous

dart

stream

iterable