From: Daniel Schierbeck <daniel.schierbeck@...>
Date: 2006-06-20T05:35:41+09:00
Subject: Re: associative array naming indirection

dan donaldson wrote:
> I have an array of names in string form as an instance var. The class 
> the array is in has a method that takes an array of string values.
> 
> I want to construct an associative array such that the names in the 
> first array are the keys to the values in the received array.
> 
> this throws an error:
> --------------
>  def initialize
>     @labels = ['prov', 'area', 'zone', district', 'postalcode', 
> 'city_prov', 'addr']
>     @pageData = {}
>   end
> 
>   def adddata(data)
>     max = data.length
>     max -= 1
>     0.upto(max) {|i| @pageData[@labels[i]] => data[i] }
>   end

   def add_data(data)
     Hash[*@labels.zip(data).flatten]
   end

Hash.[] takes an argument list with the even items being the keys and 
the odd items the values of the hash, i.e.

   Hash[:a, 1, :b, 2, :c, 3]  => {:a => 1, :b => 2, :c => 3}

The asterisk turns an array into an argument list, i.e.

   foo(*[:a, :b, :c])

is the same as

   foo(:a, :b, :c)

You can read about Array#zip and Array#flatten on the documentation 
pages, or by using ri from the terminal, e.g.

   $ ri Array#zip


Cheers,
Daniel