From: Josselin <josselin@...>
Date: 2007-01-21T00:40:05+09:00
Subject: Re: conditional value in hash array ?

On 2007-01-20 16:06:42 +0100, Wolfgang N�dasi-Donner 
<wonado@donnerweb.de> said:

> Josselin schrieb:
>> hos to have a conditional value  ?  :  :category => domain unless domain.nil?
> 
> It doesn't make sense in this situation, because "domain unless 
> domain.nil?" evauates to "nil" if "domain" contains "nil".
> 
> If you want to insert "nil" if "domain" is not yet defined use 
> something like this:
> 
> irb(main):002:0> x = (domain ||= nil)
> => nil
> irb(main):003:0> a = {:a => (domain ||= nil)}
> => {:a=>nil}
> 
>> [ :distance => radius.to_f , :category => domain unless domain.nil?, 
>> :valid_until  => Time.now.utc]
>> 
>> but giving an error....   unexpected kUNLESS_MOD, expecting ']'
> 
> In other situations you should use parenthesis ":category => (domain 
> unless domain.nil?)".
> 
> It is also possible to use the "?:" operator in some cases:
> 
> irb(main):007:0> a = [:a => (domain.nil??42:84)]
> => [{:a=>42}]
> 
> Wolfgang N�dasi-Donner

thanks Wolfgang

my objective is not entering a value in the array if the domain is nil
so it seems I should enter first nil if domain is nil as you stated  
then compact the array to get rid of nil values..