So in C#, I can treat a string[] as an IEnumerable<string>.
Is there a Java equivalent?
Add a comment
|
5 Answers
Iterable<String> is the equivalent of IEnumerable<string>.
It would be an odditity in the type system if arrays implemented Iterable. String[] is an instance of Object[], but Iterable<String> is not an Iterable<Object>. Classes and interfaces cannot multiply implement the same generic interface with different generic arguments.
String[] will work just like an Iterable in the enhanced for loop.
String[] can easily be turned into an Iterable:
Iterable<String> strs = java.util.Arrays.asList(strArray);
Prefer collections over arrays (for non-primitives anyway). Arrays of reference types are a bit odd, and are rarely needed since Java 1.5.
answered Dec 14, 2008 at 16:25
Tom Hawtin - tackline
148k30 gold badges222 silver badges314 bronze badges
3 Comments
Mark McDonald
For more info on why you cannot cast between Iterable<String> and Iterable<Object>, check out covariance and contravariance.
BrainSlugs83
Okay, so now let's address the 500-lb gorilla in the room. How do you use
Iterable<T>? -- what is the equivalent yield return statement in Java?Tom Hawtin - tackline
@BrainSlugs83 I think that's a different question.
Are you looking for Iterable<String>?
Iterable<T> <=> IEnumerable<T>
Iterator<T> <=> IEnumerator<T>
Comments
Iterable <T>
Comments
I believe the Java equivalent is Iterable<String>. Although String[] doesn't implement it, you can loop over the elements anyway:
String[] strings = new String[]{"this", "that"};
for (String s : strings) {
// do something
}
If you really need something that implements Iterable<String>, you can do this:
String[] strings = new String[]{"this", "that"};
Iterable<String> stringIterable = Arrays.asList(strings);
Comments
Iterable<T> is OK, but there is a small problem. It cannot be used easily in stream() i.e lambda expressions.
If you want so, you should get it's spliterator, and use the class StreamSupport().
