Rails - Sep 2007 - ORing of strings

Hi,

I wanted to do this: get display_name as one of those nick_name, first
and last in that order.
@display_name = @nick_name || @first_name || @second_name

but if nick_name turns out be "" and not ni. so @display_name gets
""
and not the values in first or second.

How do we handle this situation?

Regards,
Sandeep G
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Sandeep Gudibanda wrote:
> Hi,
> 
> I wanted to do this: get display_name as one of those nick_name, first
> and last in that order.
> @display_name = @nick_name || @first_name || @second_name
> 
> but if nick_name turns out be "" and not ni. so @display_name
gets ""
> and not the values in first or second.
> 
> How do we handle this situation?
> 
> Regards,
> Sandeep G
I dont really understand what you mean but why not put them in array :)

@display_name = ["nick_name", "asd", "asd"]

and then

@display_name.each do |val|
  if nil or if "" then do that or this?
end
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On Sep 7, 2007, at 1:49 AM, Sandeep Gudibanda wrote:
>
> Hi,
>
> I wanted to do this: get display_name as one of those nick_name, first
> and last in that order.
> @display_name = @nick_name || @first_name || @second_name
>
> but if nick_name turns out be "" and not ni. so @display_name
gets ""
> and not the values in first or second.
>
> How do we handle this situation?
>
> Regards,
> Sandeep G
I handle this by creating a String#nonblank? to work like  
Numeric#nonzero? (see docs)

class String
   # Allowing a chain like: string_value.nonblank? || ''default
value''
   def nonblank?
     self unless blank?
   end
end

and to duck-type when nil:

class NilClass
   # Allowing a chain like: value.nonblank? || ''default value''
   def nonblank?
     self
   end
   # so it plays nicely with Numeric#nonzero?
   def nonzero?
     self
   end
end

Then your example becomes:

@nick_name = nil
@first_name = ""
@second_name = "Sandeep"

 >> @display_name = @nick_name.nonblank? || @first_name.nonblank? ||  
@second_name.nonblank?
=> "Sandeep"

You can actually leave the .nonblank? off of the last part if you  
don''t care nil v. '''' depending on @second_name.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org




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