How do I iterate over a stream in Java using for? [duplicate]

Question

I have this code:

List<String> strings = Arrays.asList("a", "b", "cc"); for (String s : strings) {     if (s.length() == 2)         System.out.println(s); } 

I want to write it using a filter and a lambda:

for (String s : strings.stream().filter(s->s.length() == 2)) {     System.out.println(s); } 

I get Can only iterate over an array or an instance of java.lang.Iterable.

I try:

for (String s : strings.stream().filter(s->s.length() == 2).iterator()) {     System.out.println(s); } 

And I get the same error. Is this even possible? I would really prefer not to do stream.forEach() and pass a consumer.

Edit: it's important to me not to copy the elements.

Answer 1

You need an iterable to be able to use a for-each loop, for example a collection or an array:

for (String s : strings.stream().filter(s->s.length() == 2).toArray(String[]::new)) { 

Alternatively, you could completely get rid of the for loop:

strings.stream().filter(s->s.length() == 2).forEach(System.out::println); 

You mention you don't want to refactor your for loop but you could extract its body in another method:

strings.stream().filter(s->s.length() == 2).forEach(this::process);  private void process(String s) {   //body of the for loop }