On 27.05.2007 11:44, H?vard Moen wrote:
> Alex Young <alex / blackkettle.org> wrote:
>> H?vard Moen wrote:
>>> When I use String.scan with a block and just one group the result ends
>>> up as an array. More than one group works as expected. A small example to 
>>> demonstrate:
>>>
>>> --ruby code start--
>>> data = '   lb method member observed
>>>    monitor all http
>>>    member 192.168.1.68:http'
>>> data.scan(/monitor all (.*)$/) do |monitor|
>>>   puts monitor.inspect
>>> end
>>> data.scan(/member ([0-9.]+):(.*)/) do |adress, port|
>>>   puts adress.inspect
>>>   puts port.inspect
>>> end
>>> --ruby code end--
>>>
>>> gives me:
>>> ["http"]
>>> "192.168.1.68"
>>> "http"
>> That's expected.  What scan actually yields to the block is an array, 
>> and in your second example that array is being automatically split into 
>> its component parts because you've given more than one block parameter 
>> in the pipes.  A third example should make it clear:
>>
>> irb(main):004:0> data.scan(/member ([0-9.]+):(.*)/) do |match|
>> irb(main):005:1*   puts match.inspect
>> irb(main):006:1> end
>> ["192.168.1.68", "http"]
>>
> 
> Ok, but is there a way to get just the string without using something
> like monitor = monitor[0] at the start of the block?

Use only capturing groups for what you want to capture.  For all others 
use non capturing groups.  This sounds trivial but it's actually as easy 
as that. :-)

In case you haven't seen non capturing groups yet:

irb(main):002:0> "cababab".scan(/(.)(?:ab)+/) {|m| p m}
["c"]
=> "cababab"

Kind regards

	robert