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comp.lang.ruby

String.to_sym?

robertj

12/12/2005 3:10:00 PM

hi,

is there a String#to_sym method anywhere in the
statndard lib? i couldnt find anything like that
but maybe i missed it.

its easy enough to write

class String
def to_sym
eval ":#{self}"
end
end

just want to check if its there already.

ciao robertj
7 Answers

Mark J. Reed

12/12/2005 3:25:00 PM

0

"robertj" <robert_kuzelj@yahoo.com> writes:

>hi,

>is there a String#to_sym method anywhere in the
>statndard lib? i couldnt find anything like that
>but maybe i missed it.

It's called "intern", because Ruby internalizes the string into a symbol.
And it's rather more efficient than the eval method you propose.

irb(main):001:0> "somestring".intern
=> :somestring

Nobuyoshi Nakada

12/12/2005 3:35:00 PM

0

Hi,

At Tue, 13 Dec 2005 00:27:38 +0900,
Mark J.Reed wrote in [ruby-talk:170247]:
> >is there a String#to_sym method anywhere in the
> >statndard lib? i couldnt find anything like that
> >but maybe i missed it.
>
> It's called "intern", because Ruby internalizes the string into a symbol.

String#to_sym is also an alias in 1.8 or later.

--
Nobu Nakada

MenTaLguY

12/12/2005 6:04:00 PM

0

Quoting robertj <robert_kuzelj@yahoo.com>:

> hi,
>
> is there a String#to_sym method anywhere in the
> statndard lib? i couldnt find anything like that
> but maybe i missed it.

If you've got a reasonably recent version of Ruby, yes. I don't
know about 1.6 or earlier.

> its easy enough to write
>
> class String
> def to_sym
> eval ":#{self}"
> end
> end

If you had to write one yourself, you'd want:

class String
alias to_sym intern
end

eval'ing ":#{self}" won't work if the string has spaces or anything
like that. In general, eval'ing strings should be an absolute last
resort in code, because it is very difficult to make reliable.

-mental

Trans

12/12/2005 6:25:00 PM

0

Hmm... What version of Ruby are you using? You should be able to use
String#to_sym presently.

Originally the method for doing so was #intern. Though I haven't heard
any specific verbage to the effect from offical sources, I would highly
recommend never using #intern again. Use #to_sym instead.

T.

Christian Neukirchen

12/12/2005 8:06:00 PM

0

mental@rydia.net writes:

> Quoting robertj <robert_kuzelj@yahoo.com>:
>
>> hi,
>>
>> is there a String#to_sym method anywhere in the
>> statndard lib? i couldnt find anything like that
>> but maybe i missed it.
>
> If you've got a reasonably recent version of Ruby, yes. I don't
> know about 1.6 or earlier.
>
>> its easy enough to write
>>
>> class String
>> def to_sym
eval ":#{dump}"
>> end
>> end
>
> eval'ing ":#{self}" won't work if the string has spaces or anything
> like that. In general, eval'ing strings should be an absolute last
> resort in code, because it is very difficult to make reliable.
>
> -mental
>

--
Christian Neukirchen <chneukirchen@gmail.com> http://chneuk...

robertj

12/13/2005 10:28:00 AM

0

hi,

obviously its there IF you try to call it.
prblem on my side was that i looked in the docs
http://www.ruby-doc.org/docs/Progra...
and there is no mention of #to_sym anywhere
so i thought its no available.
my fault :-)

ciao robertj

Trans

12/13/2005 2:39:00 PM

0


robertj wrote:
> hi,
>
> obviously its there IF you try to call it.
> prblem on my side was that i looked in the docs
> http://www.ruby-doc.org/docs/Progra...
> and there is no mention of #to_sym anywhere
> so i thought its no available.
> my fault :-)

I see. FYI for the future. The best place to check first is always
using ri:

$ ri to_sym

More than one method matched your request. You can refine
your search by asking for information on one of:

Fixnum#to_sym, String#to_sym, Symbol#to_sym

$ ri String#to_sym

....

T.