From: Rob Biedenharn <Rob@...>
Date: 2008-02-03T07:21:23+09:00
Subject: Re: Strings .each method


On Feb 2, 2008, at 5:14 PM, Chris Hickman wrote:

> Corey Haines wrote:
>> but if you can describe why you want to do it, there might be a  
>> different way
>
> It is kind of hard to explain but I have a long string that someone
> typed into a form which was then saved into a database.  They used  
> made
> up tags such as "<choose1>, </choose1>, <row>, </row>, <tbl> ..."  I
> have to translate the string into html and add javascript etc. based  
> on
> the different tags they wrote.
>
> I have it working for everything except one task.  In this one task I
> want to pass the words between two tags as a value for the javascript.
> The problem is it is pulling the phrase apart at every space.  I  
> know I
> can add .each(???) and have it pull everything apart at the ??? but it
> would involve a lot of adding ??? to this long string.
>
> What I am trying to do is add a while loop inside the block that will
> look ahead at the next substring to see if it is a "</choose1>".  If  
> it
> is I want it to exit the while loop and go on without throwing away  
> the
> "</choose1>" tag because it is needed next time through the block.
>
> Sorry if that didnt make sense at all.

Perhaps something like this:

irb> require 'enumerator'
=> true
irb> a = "This is a big list of words"
=> "This is a big list of words"
irb> (a.split(' ') << nil).each_cons(2) {|word,lookahead| puts "%-10s  
%s"%[word.inspect,lookahead.inspect]}
"This"     "is"
"is"       "a"
"a"        "big"
"big"      "list"
"list"     "of"
"of"       "words"
"words"    nil
=> nil

Putting the << nil gives the last word something to be spit out of the  
each_cons with.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com