From: Brian Candler <B.Candler@...>
Date: 2007-02-07T00:13:01+09:00
Subject: Re: Parse csv similar file

On Tue, Feb 06, 2007 at 11:54:59PM +0900, Rebhan, Gilbert wrote:
> > what kind of collection is the best ? is an array sufficient ?
> /*
> Depends what you want to do with it. If you want to be able to find an
> entry
> E123456 quickly, then you'd use a hash. If you want to keep only the
> first/last entry for a particular key (as it seems you do), using a hash
> speeds things up here too.
> */
> 
> i don't need to find all entries E..... , but collect all datas
> that belong to the different E.....
> 
> i want a collection for every E... that occurs, with all the lines
> (except the E... itself) that contain that E in it
> 
> /*
> Try:
> 
> efas = Hash.new
> ...
>     efas[$3] = [$1,$2,$4,$5,$6] unless efas.has_key?($3)
> ...
> puts efas.inspect
> */
> 
> that gives me only one dataset in the hash, but there are more
> entries that have E123456 in it.

I was just following your original example, which only kept the first line
for a particular E key.

If you want to keep them all, then I'd use a hash with each element being an
array.

     efas[$3] ||= []               # create empty array if necessary
     efas[$3] << [$1,$2,$4,$5,$6]  # add a new line

So, given the following input

aaa,bbb,E123,ddd,eee,fff
ggg,hhh,E123,iii,jjj,kkk

you should get

efas = {
  "E123" => [
         ["aaa","bbb","ddd","eee","fff"],
         ["ggg","hhh","iii","jjj","kkk"],
  ],
}

puts efas["E123"].size   # 2
puts efas["E123"][0][3]  # "eee"
puts efas["E123"][1][3]  # "jjj"

In practice, to make it easier to manipulate this data, you'd probably want
to create a class to represent each object, rather than using a 5-element
array.

You would give each attribute a sensible name. I don't know what these
values mean, so I've just called them a to e here.

class Myclass
  attr_accessor :a, :b, :c, :d, :e
  def initialize(a, b, c, d, e)
    @a = a
    @b = b
    @c = c
    @d = d
    @e = e
  end
end

...
     efas[$3] ||= []
     efas[$3] << Myclass.new($1,$2,$4,$5,$6)

HTH,

Brian.