# Re: testing for nil or empty and then **URL:** \ **Category:** Rails\ **Created:** [October 18, 2006, 10:40am UTC](https://www.ruby-forum.com/t/re-testing-for-nil-or-empty-and-then/72687 "2006-10-18T10:40:47Z")\ **Posts on this page:** 8\ **Page:** 1

**Author:** ![badelatng](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/c5a1d2/32.png) [@badelatng](https://www.ruby-forum.com/u/badelatng)\ **Post date:** [October 18, 2006, 10:40am UTC](https://www.ruby-forum.com/t/re-testing-for-nil-or-empty-and-then/72687/1 "2006-10-18T10:40:47Z")

Try If !params[:category\_id] || params[:category\_id].empty? If the first part of the conditional is true, Ruby will ignore the next for speed. (Careful of this if you use a function as a conditional and rely on it being run regardless of the outcome) You could probably do: If(params[:category\_id] || “”).empty If params[:category\_id] is nil, the evaluation of the parens will be “”. Ben ---

blank? is useful for all-purpose emptiness testing ---

No, that’ll blow up according to my irb session. ---

Hi – On Fri, 13 Oct 2006, Ben wrote: > No, that’ll blow up according to my irb session. If you’re talking about blank?, it’s defined in Rails but not in Ruby, so in a normal irb session it won’t be available. David – David A. Black | removed\_email\_address@domain.invalid Author of “Ruby for Rails” [1] | Ruby/Rails training & consultancy [3] DABlog (DAB’s Weblog) [2] | Co-director, Ruby Central, Inc. [4] [1] [Ruby for Rails](http://www.manning.com/black) | [3] [http://www.rubypowerandlight.com](http://www.rubypowerandlight.com) [2] [http://dablog.rubypal.com](http://dablog.rubypal.com) | [4] [http://www.rubycentral.org](http://www.rubycentral.org) ---

On 10/13/06, Ben D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > for speed. (Careful of this if you use a function as a conditional and rely > > If params[:category\_id] is nil, the evaluation of the parens will be “”. > > Ben Not sure where to go at this point. Trying the above with no success. I had also tried blank and didn’t help. Right now, using CriteriaQuery plugin my statements look like this (i removed the if statement as it was giving me a nil error): pq = Position.query pq.category\_id\_in(params[:category\_id]) pq.state\_id\_in(params[:state\_id]) pq.term\_id\_in(params[:term\_id]) pq.city\_in(params[:city].split(‘,’)) pq.title\_in(params[:title].split(‘,’)) pp pq @positions = pq.find Which seems to work on their own (without and if clause) Here I only chose one field (printout using PP): #\“positions”}, @model\_class=Position, @restrictions= [#\, @query=#\, @restrictions=[], @value=“3”\>, #\, @query=#\, @restrictions=[], @value=nil\>, #\, @query=#\, @restrictions=[], @value=nil\>, #\, @query=#\, @restrictions=[], @value=[]\>, #\, @query=#\, @restrictions=[], @value=[]\>]\> ---

**Author:** ![badelatng](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/c5a1d2/32.png) [@badelatng](https://www.ruby-forum.com/u/badelatng)\ **Post date:** [October 18, 2006, 10:44am UTC](https://www.ruby-forum.com/t/re-testing-for-nil-or-empty-and-then/72687/6 "2006-10-18T10:44:01Z")

Fantastic! I’ll use a console next time ;^) ---

**Author:** ![badelatng](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/c5a1d2/32.png) [@badelatng](https://www.ruby-forum.com/u/badelatng)\ **Post date:** [October 18, 2006, 10:44am UTC](https://www.ruby-forum.com/t/re-testing-for-nil-or-empty-and-then/72687/8 "2006-10-18T10:44:02Z")

Hey guys , woo woo ! I finally got it right. pq.category\_id\_in(params[:category\_id])unless(params[:category\_id]).empty? Unless …yep! Thanks for the help Stuart On 10/13/06, Dark A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > If(params[:category\_id] || “”).empty > > Not sure why the unless part is illegal, or is maybe it’s the assignment > after. > Perhaps there is a better way to phrase it. My thinking is to check if a > value exists first then make the assignment. > > Stuart – > **[Dark ambient](https://en.wikipedia.org/wiki/Dark_ambient)** > > Dark ambient (referred to as ambient industrial especially in the 1980s) is a genre of post-industrial music that features an ominous, dark droning and often gloomy, monumental or catacombal atmosphere, partially with discordant overtones. It shows similarities with ambient music, a genre that has been cited as a main influence by many dark ambient artists, both conceptually and compositionally. Although mostly electronically generated, dark ambient also includes the sampling of hand-pla > The te...