# Arrays, symbols and association - looking for better idiom

**URL:** <https://www.ruby-forum.com/t/arrays-symbols-and-association-looking-for-better-idiom/96435>\
**Category:** Ruby\
**Created:** [June 28, 2006, 7:44pm UTC](https://www.ruby-forum.com/t/arrays-symbols-and-association-looking-for-better-idiom/96435 "2006-06-28T19:44:12Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [June 28, 2006, 7:44pm UTC](https://www.ruby-forum.com/t/arrays-symbols-and-association-looking-for-better-idiom/96435/1 "2006-06-28T19:44:12Z")

</div>

Hi all,

I’m trying to associate non-symbol arguments with the most immediately  
previous  
symbol. The solution below works, but I suspect there’s an easier way:

def test(\*args)  
hash = {}  
current = nil  
args.each{ |arg|  
if arg.is\_a?(Symbol)  
hash[arg] = []  
current = arg  
else  
hash[current] \<\< arg  
end  
}

```
hash

```

end

hash = test(:foo, 1, :bar, ‘a’, 7, :baz, /hello/, Fixnum)

p hash # {:foo=\>[1], :bar=\>[“a”, 7], :baz=\>[/hello/, Fixnum]}

Any ideas? Some Array#assoc trick I’m missing?

Thanks,

Dan

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---

<div class="post-metadata">

**Author:** ![danielb](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/c57346/32.png) [@danielb](https://www.ruby-forum.com/u/danielb)\
**Post date:** [June 29, 2006, 7:26pm UTC](https://www.ruby-forum.com/t/arrays-symbols-and-association-looking-for-better-idiom/96435/2 "2006-06-29T19:26:48Z")

</div>

On Jun 28, 2006, at 1:15 PM, Daniel B. wrote:

> ```
> if arg.is_a?(Symbol)
> 
> ```
> 
> hash = test(:foo, 1, :bar, ‘a’, 7, :baz, /hello/, Fixnum)  
> This communication is the property of Qwest and may contain  
> confidential or  
> privileged information. Unauthorized use of this communication is  
> strictly prohibited and may be unlawful. If you have received this  
> communication in error, please immediately notify the sender by  
> reply e-mail and destroy all copies of the communication and any  
> attachments.

Well this isn’t any easier but it does use inject:

% cat ruby\_hashbuild.rb  
def test(\*args)  
args.inject([Hash.new{|h,k| h[k] = []}, nil]) do |(hash,  
current\_key), val|  
case val  
when Symbol  
current\_key = val  
else  
hash[current\_key] \<\< val  
end  
[hash, current\_key]  
end.first  
end

hash = test(:foo, 1, :bar, ‘a’, 7, :baz, /hello/, Fixnum)  
p hash

% ruby ruby\_hashbuild.rb  
{:bar=\>[“a”, 7], :baz=\>[/hello/, Fixnum], :foo=\>[1]}