From: 7stud -- <bbxx789_05ss@...>
Date: 2007-11-23T19:50:23+09:00
Subject: Re: New at regexp and Ruby need help on parsing a string.

7stud -- wrote:
>
> Try this:
> 
> str = 'and stuff and nice things not bad girls not greasy boys
> and girlsandboys'
> 
> smoking_table = {'and'=>[], 'not'=>[]}
> 
> pieces = str.split(/(and |not )/)
> len = pieces.length
> 
> index = 0
> while index < len
> 
>   case pieces[index]
>   when 'and '
>     smoking_table['and'] << pieces[index+1].strip
>     index +=2
>   when 'not '
>     smoking_table['not'] << pieces[index+1].strip
>     index += 2
>   else
>     index += 1
>   end
> 
> end
> 
> p smoking_table

Normally when you split() a string, you do something like this:

str = 'aXbXc'
pieces = str.split('X')
p pieces
-->["a", "b", "c"]

Notice that the pattern you use to split the string is not part of the 
results-it's chopped out of the string and the pieces are what's left 
over.  However, there is a little known feature where if your split 
pattern has a group in it, which is formed by putting parenthesis around 
part of the patten, then the group will be returned in the results.  I 
used parentheses around the whole split pattern to get a result array 
like this:

["", "and ", "stuff ", "and ", "nice things ", "not ", "bad girls ", 
"not ", "greasy boys\n", "and ", "girlsandboys"]

By including the split pattern in the results, you can see that each 
piece of the string is preceded by either 'and ' or 'not '.  The 'and ' 
or 'not ' then serves as an identifier for each piece of the string.

-- 
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