Forum: Ruby Better way to do this?

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Pito S. (Guest)
on 2009-02-13 00:26
Hi,

I seem to be repeating myself in the following little bit:

if (!@options[:namespace].nil?)
    namespace_options = @options[:namespace]
    root.add_namespace(namespace_options[:namespace],
namespace_options[:value])
end

Can someone show me a way to not repeat options[:namespace] ?

Simpler example of the exact same:

if (!hash[:value].nil?)
    h = hash[:value]
    puts h[:left], h[:right]
end

Thanks for any tips for writing more idiomatic ruby!
Joel VanderWerf (Guest)
on 2009-02-13 00:47
(Received via mailing list)
Pito S. wrote:
> Can someone show me a way to not repeat options[:namespace] ?
>
> Simpler example of the exact same:
>
> if (!hash[:value].nil?)
>     h = hash[:value]
>     puts h[:left], h[:right]
> end

hash = {
   :value => {:left => 1, :right => 2}
}

# original:
if (!hash[:value].nil?)
     h = hash[:value]
     puts h[:left], h[:right]
end

# looking up :value only once
h = hash[:value]
if h ## assuming you don't use false as a value in the hash
   puts h[:left], h[:right]
end

# living a little dangerously (assignment in conditional):
if (h = hash[:value])
   puts h[:left], h[:right]
end

# more compactly, if you care:
h = hash[:value] and puts h[:left], h[:right]

# the last one depends on 'and' having low precedence (unlike &&)
Bertram S. (Guest)
on 2009-02-13 00:48
(Received via mailing list)
Hi,

Am Freitag, 13. Feb 2009, 07:24:59 +0900 schrieb Pito S.:
>
> if (!hash[:value].nil?)
>     h = hash[:value]
>     puts h[:left], h[:right]
> end

Untested:

  if (!(h = hash[:value]).nil?)
    puts h[:left], h[:right]
  end

or

  h = hash[:value]
  unless h.nil? then
    puts h[:left], h[:right]
  end

or

  h = hash[:value]
  h.nil? or puts h[:left], h[:right]

Hope you enjoyed the trip.

Bertram
Tim P. (Guest)
on 2009-02-13 00:50
(Received via mailing list)
On Feb 12, 2009, at 3:24 PM, Pito S. wrote:

> Can someone show me a way to not repeat options[:namespace] ?
>
> Simpler example of the exact same:
>
> if (!hash[:value].nil?)
>    h = hash[:value]
>    puts h[:left], h[:right]
> end
>

if (h = hash[:value])
   puts h[:left], h[:right]
end


Blessings,
TwP
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