Rails - Mar 2006 - Determine if a value is an instance of String , or Array , or...

each loop inside a mixed hash
I need to determine if the value is an instance of String
How ?

hash.each do |k,v|
    if v ( instance of ) String
       hash[ k ] = v.capitalize
    enf
end

On 3/4/06, oo00oo <oo00oo@free.fr> wrote:
>
> each loop inside a mixed hash
> I need to determine if the value is an instance of String
> How ?
>
> hash.each do |k,v|
>     if v ( instance of ) String
>        hash[ k ] = v.capitalize
>     enf
> end

Here''s two different ways of doing it ... since I''m still
pretty new to
ruby, I''m not sure if either of them is the best way (both use
capitalize!
rather to capitalize to change the value "in-place"):

hash.each do |k,v|
  v.capitalize! rescue v
end

OR

hash.each do |k,v|
  v.capitalize! if v.respond_to? :capitalize
end

Rick
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Thanks for the tips
inline rescue is nice !
But I''m always searching a method to determine a type. For Arrays,
Hashs...
>
> On 3/4/06, *oo00oo* <oo00oo@free.fr <mailto:oo00oo@free.fr>>
wrote:
>
>     each loop inside a mixed hash
>     I need to determine if the value is an instance of String
>     How ?
>
>     hash.each do |k,v|
>         if v ( instance of ) String
>            hash[ k ] = v.capitalize
>         enf
>     end
>
>
> Here''s two different ways of doing it ... since I''m still
pretty new
> to ruby, I''m not sure if either of them is the best way (both use 
> capitalize! rather to capitalize to change the value "in-place"):
>
> hash.each do |k,v|
>   v.capitalize! rescue v
> end
>
> OR
>
> hash.each do |k,v|
>   v.capitalize! if v.respond_to? :capitalize
> end
>
> Rick
>

hash.each{|k,v|
  v.capitalize! if v.is_a? String
}

Or use Rick''s "duck typing" approach.


oo00oo wrote:
> each loop inside a mixed hash
> I need to determine if the value is an instance of String
> How ?
> 
> hash.each do |k,v|
>     if v ( instance of ) String
>        hash[ k ] = v.capitalize
>     enf
> end
-- 
Posted via http://www.ruby-forum.com/.

object.is_a?(ClassName) does this.

object.class returns the class.

oo00oo wrote:
> Thanks for the tips
> inline rescue is nice !
> But I''m always searching a method to determine a type. For Arrays,
> Hashs...
-- 
Posted via http://www.ruby-forum.com/.

Also worth mentioning that you can do this:

   hash.each do |k, v|
     case v
       when String
         v.capitalize
       when Array
         # do something else
       else
         # do something else again
     end
   end

Pete Yandell
http://9cays.com

On 05/03/2006, at 6:07 AM, oo00oo wrote:
> Thanks for the tips
> inline rescue is nice !
> But I''m always searching a method to determine a type. For Arrays,
> Hashs...
>>
>> On 3/4/06, *oo00oo* <oo00oo@free.fr
<mailto:oo00oo@free.fr>> wrote:
>>
>>     each loop inside a mixed hash
>>     I need to determine if the value is an instance of String
>>     How ?
>>
>>     hash.each do |k,v|
>>         if v ( instance of ) String
>>            hash[ k ] = v.capitalize
>>         enf
>>     end
>>
>>
>> Here''s two different ways of doing it ... since I''m
still pretty
>> new to ruby, I''m not sure if either of them is the best way
(both
>> use capitalize! rather to capitalize to change the value
"in-place"):
>>
>> hash.each do |k,v|
>>   v.capitalize! rescue v
>> end
>>
>> OR
>>
>> hash.each do |k,v|
>>   v.capitalize! if v.respond_to? :capitalize
>> end
>>
>> Rick
>>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

hash = {''a'' => ''bob'',
''b'' => 3, ''c'' =>
''fred'' }

hash.each_value {|d| d.capitalize! if d.is_a?(String) }
=> {"a"=>"Bob", "b"=>3,
"c"=>"Fred"}

So, to answer your question, use the is_a? (or kind_of?) method.


Bob Silva
http://www.railtie.net/
> -----Original Message-----
> From: rails-bounces@lists.rubyonrails.org [mailto:rails-
> bounces@lists.rubyonrails.org] On Behalf Of oo00oo
> Sent: Saturday, March 04, 2006 10:41 AM
> To: rails@lists.rubyonrails.org
> Subject: [Rails] Determine if a value is an instance of String , or Array
> ,or...
> 
> each loop inside a mixed hash
> I need to determine if the value is an instance of String
> How ?
> 
> hash.each do |k,v|
>     if v ( instance of ) String
>        hash[ k ] = v.capitalize
>     enf
> end
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails