This was not an omission; there was detailed discussion on the EG list in June of 2013. The definitive discussion of the Expert Group is rooted at this thread. While it seemed “obvious” (even to the Expert Group, initially) that stream() seemed to make sense on Iterable, the fact that Iterable was so general became … Read more
People have already asked the same on the mailing list ☺. The main reason is Iterable also has a re-iterable semantic, while Stream is not. I think the main reason is that Iterable implies reusability, whereas Stream is something that can only be used once — more like an Iterator. If Stream extended Iterable then … Read more
Looks like that is the best way to do it: String first = strs.iterator().next(); Great question… At first, it seems like an oversight for the Collection interface. Note that “first” won’t always return the first thing you put in the collection, and may only make sense for ordered collections. Maybe that is why there isn’t … Read more
In JDK 8+, without using any additional libs: Iterator<T> source = …; List<T> target = new ArrayList<>(); source.forEachRemaining(target::add); Edit: The above one is for Iterator. If you are dealing with Iterable, iterable.forEach(target::add);
There’s a much better answer than using spliteratorUnknownSize directly, which is both easier and gets a better result. Iterable has a spliterator() method, so you should just use that to get your spliterator. In the worst case, it’s the same code (the default implementation uses spliteratorUnknownSize), but in the more common case, where your Iterable … Read more
Iteration is a general term for taking each item of something, one after another. Any time you use a loop, explicit or implicit, to go over a group of items, that is iteration. In Python, iterable and iterator have specific meanings. An iterable is an object that has an __iter__ method which returns an iterator, … Read more
Checking for __iter__ works on sequence types, but it would fail on e.g. strings in Python 2. I would like to know the right answer too, until then, here is one possibility (which would work on strings, too): try: some_object_iterator = iter(some_object) except TypeError as te: print(some_object, ‘is not iterable’) The iter built-in checks for … Read more