Why use Array#to_enum when Array already is an Enumerable?

Question

As far as I understand the Array class already mixes in the Enumerable module.

If that's so, why isn't there [:example].next?

Why do I need to make it [:example].to_enum.next?

Because the method `next` is defined on the class `Enumerator` and not `Array`. Array mixes in Enumerable which makes the conversation to `Enumerator` possible in the first place. — Konrad Reiche, Sep 27 '13 at 14:50
Same as [this](http://stackoverflow.com/questions/2863044/what-is-the-advantage-of-creating-an-enumerable-object-using-to-enum-in-ruby)? — Cary Swoveland, Sep 27 '13 at 14:51

score 7 · Answer 1 · answered Sep 27 '13 at 14:50

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to_enum has nothing to do with Enumerable, it returns an Enumerator. Array doesn't have a next method because next is an Enumerator method, not an Enumerable method.

answered Sep 27 '13 at 14:50

Jörg W Mittag

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Thanks, I didn't know the difference between Enumerable and Enumerator! – Benedikt B Sep 27 '13 at 14:58
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@JanDvorak `to_enum` is a method of `Object` – Stefan Sep 27 '13 at 15:08

score 3 · Accepted Answer · answered Sep 27 '13 at 14:51

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Because the Enumerable module is different from the Enumerator class.

Being "Enumerable" means that the class gets a bunch of freebie methods that create "Enumerators". Compare to Java's Iterable and Iterator interfaces.

answered Sep 27 '13 at 14:51

maerics

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Enumberable, Enumerator, I overlooked that! now everything makes sense. Thank you. – Benedikt B Sep 27 '13 at 14:57

Why use Array#to_enum when Array already is an Enumerable?

2 Answers2