Question

I”m curious about why ruby returns an Enumerator instead of an Array for something that seems like Array is an obvious choice. For example:

'foo'.class
# => String

Most people think of a String as an array of chars.

'foo'.chars.class
# => Enumerator

So why does String#chars return an Enumerable instead of an Array? I’m assuming somebody put a lot of thought into this and decided that Enumerator is more appropriate but I don’t understand why.

Answer 1

This completely in accordance with the spirit of 1.9: to return enumerators whenever possible. String#bytes, String#lines, String#codepoints, but also methods like Array#permutation all return an enumerator.

In ruby 1.8 String#to_a resulted in an array of lines, but the method is gone in 1.9.