From: Robert Klemme <shortcutter@...>
Date: 2011-01-20T22:10:49+09:00
Subject: Re: Problem populating a hash with regex results

On Thu, Jan 20, 2011 at 1:41 PM, RichardOnRails
<RichardDummyMailbox58407@uscomputergurus.com> wrote:
> On Jan 19, 5:10 am, Robert Klemme <shortcut...@googlemail.com> wrote:
>> On Mon, Jan 17, 2011 at 5:40 AM, RichardOnRails
>>
>> <RichardDummyMailbox58...@uscomputergurus.com> wrote:
>> > This is my current idea for succinct code to support further data
>> > analysis:
>>
>> >        field_names =%w<Name Shares Opened_MDY Closed_MDY Proceeds Cost
>> > GainLoss>
>> >        h = {}
>> >        (1..field_names.size).each { |name| h[name] = eval($ + ito_s) }
>>
>> > Of course, that doesn't work,  but despite my perusing of Pragmatic's
>> > Programming Ruby, 2nd ed.,  I haven't so far figured out how to code
>> > that third line.  Any ideas.  If you're too busy, or whatever,  don't
>> > bother responding and I'll post about it tomorrow.
>>
>> If you are on 1.9 there is a better approach: named capture groups.
>> These let you use your MatchData object like a Hash:
>>
>> Ruby version 1.9.2
>> irb(main):001:0> rx = /(?'name'\w+)\s*=\s*(?'value'\S+)/
>> => /(?'name'\w+)\s*=\s*(?'value'\S+)/
>> irb(main):002:0> md = rx.match " foo = 123 "
>> => #<MatchData "foo = 123" name:"foo" value:"123">
>> irb(main):003:0> md[:name]
>> => "foo"
>> irb(main):004:0> md[:value]
>> => "123"
>> irb(main):005:0> md.names
>> => ["name", "value"]
>> irb(main):006:0>
>>
>> Note, there is an alternative syntax: (?<a name>rx)
>>
>> Seehttp://www.geocities.jp/kosako3/oniguruma/doc/RE.txt
>>
>> Kind regards
>>
>> robert
>>
>> --
>> remember.guy do |as, often| as.you_can - without endhttp://blog.rubybestpractices.com/
>
> Hi Robert,
>
> Thanks for your response.  I didn't notice your reply because gave up
> on this thread and restarted on
> http://groups.google.com/group/comp.lang.ruby/browse_thread/thread/6ddcea45d88ad810.
>
> I'm still running 1.8.6 'cause it's worked well for me.  Like the song
> advises, "ya gotta dance with the guy that brung you."  But I've copy
> your advice to apply it after this project's done, at which time I'll
> upgrade to 1.9.x.

Well, let's see what we can do...

irb(main):001:0> MDWrap = Struct.new :md, :fields do
irb(main):002:1* def [](name) md[fields[name]] end
irb(main):003:1> end
=> MDWrap
irb(main):004:0> md = MDWrap.new("foobar".match(/(fo+)(ba\w+)/),
:name=>1,:value=>2)
=> #<struct MDWrap md=#<MatchData "foobar" 1:"foo" 2:"bar">,
fields={:value=>2, :name=>1}>
irb(main):005:0> md[:name]
=> "foo"

or

irb(main):007:0> names = {:name => 1, :value => 2}
=> {:value=>2, :name=>1}
irb(main):008:0> md = "foobar".match(/(fo+)(ba\w+)/)
=> #<MatchData "foobar" 1:"foo" 2:"bar">
irb(main):009:0> md[names[:name]]
=> "foo"

Or you use indexes directly.

:-)

Cheers

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/