Re: A tad of meta-programming needed

On Sun, Jan 16, 2011 at 11:30 PM, RichardOnRails <
[e-mail]> wrote:

> I've got the following hash set up and it works fine.  But this took
> more typing than programming.
>
>        h = {:name=>$1,  :n_shares=>$2,  :opened_MDY=>$3,  :closed_MDY=>$4,
>                :proceeds=>$5,  :cost=> $6,   :gain_Loss=>$7
>              }
>
> So I'd like to get the following to work:
>
>        field_names =%w<Name Shares Opened_MDY Closed_MDY Proceeds Cost
> GainLoss>
>        h = {}
>        (1..field_names.size).each { |i| h[field_names[i]] = eval($ +
> i.to_s) }
>
> But concatenating the character "$" with the value of i converted to a
> string, followed be evaluating that as a local variable isn't working
> as I coded it.  Can it be easily corrected?
>
> Thanks in Advance,
> Richard
>
>

The matchdata object implements the same inteface as a hash. If that is all
you need, on 1.9 you could just name the capture groups, then use the
MatchData object and not have to do any assignment/creation at all.
(Assuming this data is based on the pastie you posted earlier, this code
would work)


RUBY_VERSION # => "1.9.2"

line = "Apple 1.1234 1/2/3 4/5/6 $1,234.56 $7 ($5)"

regex = /^(?<name>       .+                       )\s
          (?<n_shares>   \d+\.\d{4}               )\s+
          (?<opened_MDY> \d\d?\/  \d\d?\/  \d\d?  )\s+
          (?<closed_MDY> \d\d?\/  \d\d?\/  \d\d?  )\s+
          (?<proceeds>   [\$\d,\.]+               )\s+
          (?<cost>       [\$\d,\.]+               )\s+
          (?<gain_Loss>  [\(\)\$,\d \.]+          )\s*
        $/x

result = regex.match(line)
result                      # => #<MatchData "Apple 1.1234 1/2/3 4/5/6
$1,234.56 $7 ($5)" name:"Apple" n_shares:"1.1234" opened_MDY:"1/2/3"
closed_MDY:"4/5/6" proceeds:"$1,234.56" cost:"$7" gain_Loss:"($5)">
result[ :name       ]       # => "Apple"
result[ :n_shares   ]       # => "1.1234"
result[ :opened_MDY ]       # => "1/2/3"
result[ :closed_MDY ]       # => "4/5/6"
result[ :proceeds   ]       # => "$1,234.56"
result[ :cost       ]       # => "$7"
result[ :gain_Loss  ]       # => "($5)"