I've just been tripped up by this behaviour, which I haven't
seen documented anywhere:

"hello".to_a #=> ["hello"]
"".to_a #=> []

Why does an empty string get omitted from the array?
Why doesn't Enumerable#to_a document this behaviour of strings?
This is completely broken (Ruby 1.8.6)

This affected me in a call to send() using a splat - it always
works ok except when the parameter list is an empty string :-(.

Clifford Heath.

On 3/11/08, Clifford Heath <no@spam.please.net> wrote:
> I've just been tripped up by this behaviour, which I haven't
> seen documented anywhere:
>
> "hello".to_a #=> ["hello"]
> "".to_a #=> []
>
> Why does an empty string get omitted from the array?
> Why doesn't Enumerable#to_a document this behaviour of strings?
> This is completely broken (Ruby 1.8.6)

I disagree. #to_a doesn't just encase the string object in an
otherwise empty array, rather it casts the string to an array, as
appropriate:

"".to_a => []
"test".to_a => ["test"]
"this\nis\na\n\test".to_a => ["this\n", "is\n", "a\n", "test"]

The array equivalent of an empty string is an empty array. Both, for
instance, have a #size of 0.

Christopher

Christopher Swasey wrote:
> On 3/11/08, Clifford Heath <no@spam.please.net> wrote:
>> I've just been tripped up by this behaviour, which I haven't
>> seen documented anywhere:
>>
>> "hello".to_a #=> ["hello"]
>> "".to_a #=> []
>>
>> Why does an empty string get omitted from the array?
>> Why doesn't Enumerable#to_a document this behaviour of strings?
>> This is completely broken (Ruby 1.8.6)
>
> I disagree. #to_a doesn't just encase the string object in an
> otherwise empty array, rather it casts the string to an array, as
> appropriate:
>
> "".to_a => []
> "test".to_a => ["test"]
> "this\nis\na\n\test".to_a => ["this\n", "is\n", "a\n", "test"]
>
> The array equivalent of an empty string is an empty array. Both, for
> instance, have a #size of 0.

To add to that: the way I've understood it is that, in the context of a
String, the Enumerable methods treat it as an enumeration of lines.

--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407

Joel VanderWerf wrote:
> To add to that: the way I've understood it is that, in the context of a
> String, the Enumerable methods treat it as an enumeration of lines.

Right, that does make sense now, thanks folk.
Enumerable is built on #each, and String#each does that.

Clifford Heath.