Sql – Oracle SQL – Parsing a name string and converting it to first initial & last name

You can use Ruby's open classes to make your code much more readable. For instance, this:

class String
  def initial
    self[0,1]
  end
end

will allow you to use the initial method on any string. So if you have the following variables:

last_name = "Smith"
first_name = "John"

Then you can get the initials very cleanly and readably:

puts first_name.initial   # prints J
puts last_name.initial    # prints S

The other method mentioned here doesn't work on Ruby 1.8 (not that you should be using 1.8 anymore anyway!--but when this answer was posted it was still quite common):

puts 'Smith'[0]           # prints 83

Of course, if you're not doing it on a regular basis, then defining the method might be overkill, and you could just do it directly:

puts last_name[0,1] 

Use

[A-Z]?

to make the letter optional. {1} is redundant. (Of course you could also write [A-Z]{0,1} which would mean the same, but that's what the ? is there for.)

You could improve your regex to

^([0-9]{5})+\s+([A-Z]?)\s+([A-Z])([0-9]{3})([0-9]{3})([A-Z]{3})([A-Z]{3})\s+([A-Z])[0-9]{3}([0-9]{4})([0-9]{2})([0-9]{2})

And, since in most regex dialects, \d is the same as [0-9]:

^(\d{5})+\s+([A-Z]?)\s+([A-Z])(\d{3})(\d{3})([A-Z]{3})([A-Z]{3})\s+([A-Z])\d{3}(\d{4})(\d{2})(\d{2})

But: do you really need 11 separate capturing groups? And if so, why don't you capture the fourth-to-last group of digits?