From: Robert Klemme <shortcutter@...>
Date: 2011-03-04T02:55:23+09:00
Subject: Re: How to assign an element to a hash only if its value is not nil?

On 03.03.2011 18:38, Mike Moore wrote:
> On Thu, Mar 3, 2011 at 10:10 AM, Thomas W.<thomas@thomas-witt.com>  wrote:
>>
>> hash = {}
>>     hash[:key] = myvalue
>>
>>
>> How to assign hash[:key] only if myvalue is not nil?
>>
>> Current solution is:
>>
>>     hash[:key] = myvalue unless myvalue.nil?
>>
>>
>> Is there something more beautiful?
>
> You could assign the all values and then remove the just the nil
> values afterward.
>
>    >>  h = { :one =>  1, :two =>  2, :three =>  nil, :four =>  4, :five =>  nil }
>    =>  {:three=>nil, :four=>4, :five=>nil, :one=>1, :two=>2}
>    >>  h[:six] = 6
>    =>  6
>    >>  h[:seven] = nil
>    =>  nil
>    >>  h.delete_if { |k, v| v.nil? }
>    =>  {:four=>4, :six=>6, :one=>1, :two=>2}

Oh, this is so ugly.  And also potentially inefficient since the hash 
table might grow larger than needed.

Cheers

	robert

-- 
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