From: Robert Klemme <shortcutter@...>
Date: 2007-05-04T17:00:06+09:00
Subject: Re: Is there a better way to do this?

On 04.05.2007 02:43, Michael W. Ryder wrote:
> As part of my learning Ruby I am trying to learn how to format strings. 
>  The following is an example for formatting a U.S. phone number:
> 
> a = "1234567890"
> b = "(000) 000-0000"
> ai = 0
> 
> for i in 0..(b.length) -1
>   if b[i,1] == "0"
>     b[i,1] = a[ai,1]
>     ai += 1
>   end
> end
> puts b
> 
> Is there a better (more Rubyish) way to do this?
> Obviously I will want to add more code in the future to handle 
> exceptions like phone numbers that are not 10 characters long or are 
> longer, but this will get me started.

I'd start by having the parts of the number separate.  Then you can 
easily use sprintf for the formatting.  For example, with

Phone = Struct.new(:country, :area, :number) do
   def to_s
     sprintf("(%d) %d-%d", country, area, number)
   end
end

You can do

irb(main):006:0> a = Phone.new 123, 456, 7890
=> #<struct Phone country=123, area=456, number=7890>
irb(main):007:0> puts a
(123) 456-7890
=> nil
irb(main):008:0>

You can even add exceptions and special handling if one of the parts is 
missing etc.  If you need leading zeros, that's easy with sprintf as well.

Kind regards

	robert