From: Brian Candler <B.Candler@...>
Date: 2007-05-04T16:42:31+09:00
Subject: Re: Is there a better way to do this?

On Fri, May 04, 2007 at 09:45:04AM +0900, 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?

I have a vague recollection that Perl has a specific feature along these
lines: ah yes, see "man perlform". But I've never used it, and I think this
is one Perlism that Ruby hasn't copied.

It sounds to me like you actually want two different types of format:

format("000 000-0000","1234567890") # => "123 456-7890"
format("000000.00","1234.4")        # => "  1234.40"

People have given you several solutions for the former. The latter is most
easily handled by sprintf (or format % [values]) if the value is numeric.

Actually, you could bend sprintf to do the former too:

val = "1234567890"
fmt = "(000) 000-0000"
res = sprintf(fmt.gsub(/0/,"%s"), *val.split(//))

Regards,

Brian.