除了protonpack之外，jOOλ的Seq也提供了这种功能(通过在其上构建的扩展库，如cyclops-react，我是这个库的作者)。

Seq.seq(Stream.of(names)).zipWithIndex()
                         .filter( namesWithIndex -> namesWithIndex.v1.length() <= namesWithIndex.v2 + 1)
                         .toList();

Seq还只支持Seq.of(names)，并将在幕后构建一个JDK流。

简单反应的等效物看起来类似

 LazyFutureStream.of(names)
                 .zipWithIndex()
                 .filter( namesWithIndex -> namesWithIndex.v1.length() <= namesWithIndex.v2 + 1)
                 .toList();

简单反应版本更适合异步/并发处理。

如果您不介意使用第三方库，Eclipse Collections有zipWithIndex和forEachWithIndex可供跨多种类型使用。下面是针对JDK类型和Eclipse Collections类型使用zipWithIndex的一组解决方案。

String[] names = { "Sam", "Pamela", "Dave", "Pascal", "Erik" };
ImmutableList<String> expected = Lists.immutable.with("Erik");
Predicate<Pair<String, Integer>> predicate =
    pair -> pair.getOne().length() <= pair.getTwo() + 1;

// JDK Types
List<String> strings1 = ArrayIterate.zipWithIndex(names)
    .collectIf(predicate, Pair::getOne);
Assert.assertEquals(expected, strings1);

List<String> list = Arrays.asList(names);
List<String> strings2 = ListAdapter.adapt(list)
    .zipWithIndex()
    .collectIf(predicate, Pair::getOne);
Assert.assertEquals(expected, strings2);

// Eclipse Collections types
MutableList<String> mutableNames = Lists.mutable.with(names);
MutableList<String> strings3 = mutableNames.zipWithIndex()
    .collectIf(predicate, Pair::getOne);
Assert.assertEquals(expected, strings3);

ImmutableList<String> immutableNames = Lists.immutable.with(names);
ImmutableList<String> strings4 = immutableNames.zipWithIndex()
    .collectIf(predicate, Pair::getOne);
Assert.assertEquals(expected, strings4);

MutableList<String> strings5 = mutableNames.asLazy()
    .zipWithIndex()
    .collectIf(predicate, Pair::getOne, Lists.mutable.empty());
Assert.assertEquals(expected, strings5);

下面是一个使用forEachWithIndex的解决方案。

MutableList<String> mutableNames =
    Lists.mutable.with("Sam", "Pamela", "Dave", "Pascal", "Erik");
ImmutableList<String> expected = Lists.immutable.with("Erik");

List<String> actual = Lists.mutable.empty();
mutableNames.forEachWithIndex((name, index) -> {
        if (name.length() <= index + 1)
            actual.add(name);
    });
Assert.assertEquals(expected, actual);

如果您将上述lambdas更改为匿名内部类，那么所有这些代码示例都可以在Java 5 - 7中工作。

注意:我是Eclipse Collections的提交者

正如jean-baptiste-yunès所说，如果您的流是基于java列表的，那么使用AtomicInteger及其incrementAndGet方法是一个很好的解决问题的方法，并且返回的整数与原始列表中的索引对应，只要您不使用并行流。

为了完整起见，这里是涉及我的StreamEx库的解决方案:

String[] names = {"Sam","Pamela", "Dave", "Pascal", "Erik"};
EntryStream.of(names)
    .filterKeyValue((idx, str) -> str.length() <= idx+1)
    .values().toList();

这里我们创建了一个EntryStream<Integer, String>，它扩展了Stream<Entry<Integer, String>>，并添加了一些特定的操作，如filterKeyValue或values。也使用了toList()快捷方式。

自番石榴21起，就可以使用了

Streams.mapWithIndex()

示例(来自官方文档):

Streams.mapWithIndex(
    Stream.of("a", "b", "c"),
    (str, index) -> str + ":" + index)
) // will return Stream.of("a:0", "b:1", "c:2")

String[] namesArray = {"Sam","Pamela", "Dave", "Pascal", "Erik"};
String completeString
         =  IntStream.range(0,namesArray.length)
           .mapToObj(i -> namesArray[i]) // Converting each array element into Object
           .map(String::valueOf) // Converting object to String again
           .collect(Collectors.joining(",")); // getting a Concat String of all values
        System.out.println(completeString);

山姆，帕梅拉，戴夫，帕斯卡，埃里克

String[] namesArray = {"Sam","Pamela", "Dave", "Pascal", "Erik"};

IntStream.range(0,namesArray.length)
               .mapToObj(i -> namesArray[i]) // Converting each array element into Object
               .map(String::valueOf) // Converting object to String again
               .forEach(s -> {
                //You can do various operation on each element here
                System.out.println(s);
               }); // getting a Concat String of all 

收集清单:

String[] namesArray = {"Sam","Pamela", "Dave", "Pascal", "Erik"};
 List<String> namesList
                =  IntStream.range(0,namesArray.length)
                .mapToObj(i -> namesArray[i]) // Converting each array element into Object
                .map(String::valueOf) // Converting object to String again
                .collect(Collectors.toList()); // collecting elements in List
        System.out.println(listWithIndex);