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Joshua Muheim

2008-Aug-27 22:12 UTC

"||" equivalent for .blank?

Hi all

Is there an equivalent to the || thing?

var = nil || "blah"
# => "blah"

var = "" || "blah"
# => ""

I want something like that:

var = nil ||| "blah"
# => "blah"

var = "" ||| "blah"
# => "blah"

Is there something like that in Rails? :-)

Thanks
Josh
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Ryan Bigg

2008-Aug-27 22:21 UTC

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Re: "||" equivalent for .blank?

To my knowledge, there is not.

var = "blah" if var.blank?

will however do what you want

On 28/08/2008, at 7:42 AM, Joshua Muheim wrote:
>
> Hi all
>
> Is there an equivalent to the || thing?
>
> var = nil || "blah"
> # => "blah"
>
> var = "" || "blah"
> # => ""
>
> I want something like that:
>
> var = nil ||| "blah"
> # => "blah"
>
> var = "" ||| "blah"
> # => "blah"
>
> Is there something like that in Rails? :-)
>
> Thanks
> Josh
> --  
> Posted via http://www.ruby-forum.com/.
>
> >

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Xavier Noria

2008-Aug-27 22:23 UTC

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Re: "||" equivalent for .blank?

On Thu, Aug 28, 2008 at 12:12 AM, Joshua Muheim
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
> Is there an equivalent to the || thing?
>
> var = nil || "blah"
> # => "blah"
>
> var = "" || "blah"
> # => ""
>
> I want something like that:
>
> var = nil ||| "blah"
> # => "blah"
>
> var = "" ||| "blah"
> # => "blah"
This is logically equivalent, though not as pretty

   var = a.blank? ? b : a

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Joshua Muheim

2008-Aug-27 22:32 UTC

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Re: "||" equivalent for .blank?

Xavier Noria wrote:> On Thu, Aug 28, 2008 at 12:12 AM, Joshua Muheim
> <rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
> 
>> var = nil ||| "blah"
>> # => "blah"
>>
>> var = "" ||| "blah"
>> # => "blah"
> 
> This is logically equivalent, though not as pretty
> 
>    var = a.blank? ? b : a
Thanks. But isn''t there a way to extend ruby so it can handle
"|||"?
-- 
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Xavier Noria

2008-Aug-27 22:55 UTC

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Re: "||" equivalent for .blank?

On Thu, Aug 28, 2008 at 12:32 AM, Joshua Muheim
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
> Thanks. But isn''t there a way to extend ruby so it can handle
"|||"?
In Ruby some "operators" are syntactic sugar for methods, for example
"<<", or "+". But there''s no way to go in the
other direction. That
is, you cannot define a method in Object named "|||" and tell Ruby it
should be parsed as an operator of such and such arity, etc.

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Joshua Muheim

2008-Aug-27 22:57 UTC

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Re: "||" equivalent for .blank?

Xavier Noria wrote:> On Thu, Aug 28, 2008 at 12:32 AM, Joshua Muheim
> <rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
> 
>> Thanks. But isn''t there a way to extend ruby so it can handle
"|||"?
> 
> In Ruby some "operators" are syntactic sugar for methods, for
example
> "<<", or "+". But there''s no way to go
in the other direction. That
> is, you cannot define a method in Object named "|||" and tell
Ruby it
> should be parsed as an operator of such and such arity, etc.
What a pitty... Thanks though!
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Xavier Noria

2008-Aug-27 23:58 UTC

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Re: "||" equivalent for .blank?

On Thu, Aug 28, 2008 at 12:57 AM, Joshua Muheim
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
> What a pitty... Thanks though!
Of course if a method is good for you this is doable

    class Object
      def bor(other)
        blank? ? other : self
      end
    end

    nil.bor("blah")          # => "blah"
    ''''.bor({}).bor("blah")   # =>
"blah"
    [].bor("blah").bor(true) # => "blah"

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Rob Biedenharn

2008-Aug-28 04:20 UTC

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Re: "||" equivalent for .blank?

On Aug 27, 2008, at 6:12 PM, Joshua Muheim wrote:> Hi all
>
> Is there an equivalent to the || thing?
>
> var = nil || "blah"
> # => "blah"
>
> var = "" || "blah"
> # => ""
>
> I want something like that:
>
> var = nil ||| "blah"
> # => "blah"
>
> var = "" ||| "blah"
> # => "blah"
>
> Is there something like that in Rails? :-)
>
> Thanks
> Josh

Like the Numeric#nonzero? that is useful in chained comparisons, you  
can define nonblank? to be similar and get this effect:

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

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

Since you''re already Rails, you''re already ActiveSupport and
blank?
will be well defined.

irb> nil.nonblank? || "blah"
=> "blah"
irb> "".nonblank? || "blah"
=> "blah"
irb> "foo".nonblank? || "blah"
=> "foo"

-Rob

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

Joshua Muheim

2008-Aug-28 10:10 UTC

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Re: "||" equivalent for .blank?

Thanks guys, I just found the blank? method. :-)
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Duff OMelia

2012-Feb-22 20:09 UTC

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Re: "||" equivalent for .blank?

In Rails you can now do this:

params[:state].presence || params[:country].presence || ''US''

http://apidock.com/rails/Object/presence

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Rails - Aug 2008 - "||" equivalent for .blank?

"||" equivalent for .blank?

Re: "||" equivalent for .blank?

Re: "||" equivalent for .blank?

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