String.to_sym?

robertj · December 12, 2005, 4:15pm

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

robertj · December 12, 2005, 4:30pm

“robertj” [email protected] 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

robertj · December 12, 2005, 4:36pm

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.

robertj · December 12, 2005, 7:07pm

Quoting robertj [email protected]:

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

robertj · December 12, 2005, 7:28pm

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.

robertj · December 12, 2005, 9:07pm

[email protected] writes:

its easy enough to write

class String
def to_sym
eval “:#{dump}”

robertj · December 13, 2005, 11:33am

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/ProgrammingRuby/
and there is no mention of #to_sym anywhere
so i thought its no available.
my fault

ciao robertj

robertj · December 13, 2005, 3:43pm

robertj wrote:

hi,

obviously its there IF you try to call it.
prblem on my side was that i looked in the docs
Programming Ruby: The Pragmatic Programmer's Guide
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

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