Question

I need to develop method that extracts the meaning from a string for a record in a database. Here is an example of the a string:

MyString = "Purse $75,000. (up To $14,250 Nysbfoa) For Maidens, Fillies And Mares Three Years Old And Upward. Three Year Olds, 118 Lbs.; Older, 123 Lbs. One And One Eighth Miles. (Inner turf)"    

Given the string, I need to process it in such a way that I can create a race_record:

race_record[:purse] = 75000 
race_record[:race_type] = "Maidens"
race_record[:sex] = "Fillies And Mares"
race_record[:age] = "Three Year Old And Upward"
race_record[:distance] = "One And One Eighth Miles"
race_record[:surface] = "inner turf"

I was planning on to use ruby and a series of regular expressions to extract the data. For example:

race_record[:purse] = Mystring.scan(/(?<=\Purse\s[$])(.*?)(?=\.)/)
race_record[:race_type] = Mystring.sub(....)
etc.

My question isn’t so much what the correct regular expressions are. Given the objective, is the approach I proposed the right way to go, or is there a better approach or even a gem that can do the heavy lifting?

Answer 1

You could use one regex to extract all the relevant parts into capturing groups at once;

regexp = 
    /Purse\s\$          # Leading text
    ([\d,]+)            # Group 1
    .*?For\s            # Intervening text
    (\w+)               # Group 2
    ,\s                 # Intervening text
    (\w+\sAnd\s\w+)     # Group 3, etc. etc.
    \s
    ([^.]*)
    \.[^;]*;[^.]*\.\s
    ([^.]*)
    \.\s\(
    ([^()]*)
    \)/x

Then you can do

irb(main):025:0> match = regexp.match(mystring)
=> #<MatchData "Purse $75,000. (up To $14,250 Nysbfoa) For Maidens, Fillies And    Mares Three Years Old And Upward. Three Year Olds, 118 Lbs.; Older, 123 Lbs. One And One Eighth Miles. (Inner turf)" 
   1:"75,000" 2:"Maidens" 3:"Fillies And Mares" 4:"Three Years Old And Upward" 
   5:"One And One Eighth Miles" 6:"Inner turf">
irb(main):026:0> match[1]
=> "75,000"
irb(main):027:0> match[2]
=> "Maidens"
...etc.