From: "Michael W. Ryder" <_mwryder@...>
Date: 2007-05-04T15:15:05+09:00
Subject: Re: Is there a better way to do this?

William James wrote:
> On May 3, 9:03 pm, "Michael W. Ryder" <_mwry...@worldnet.att.net>
> wrote:
>> Dan Zwell wrote:
>>>> I am trying to come up with a "generic" formatting routine so that I
>>>> could feed it something like sform("123456789", "000-00-0000") or
>>>> sform("1234567890", "(000) 000-0000") or sform("123456", "00/00/00")
>>>> and it would work.  I could easily do something like you suggest, and
>>>> for some cases it might be better, but I want something I can for any
>>>> number of formats.  Thanks for the input.
>>> welcome.
>>> require 'enumerator'
>>> def sform(num, fmt)
>>>   # convert num to array (of one digit strings):
>>>   num = num.to_enum(:each_byte).map { |code| code.chr }
>>>   # for each zero, replace it with a digit popped off the
>>>   # front of the array of numbers (or characters):
>>>   fmt.gsub(/0/) { num.shift }
>>> end
>>> dan
>> Your method is much better than my C style one.  With a little work to
>> handle exceptions it should generally work.  The only problem I have
>> found so far is that it doesn't handle periods in the number string
>> properly -- i.e. sform("12345.67", "$00,000.00") returns $12,345..6"
>> instead of $12,345.67".  Something for me to work on.  Thanks for the code.
> 
> I made some changes to handle the decimal point
> and the case when there are fewer digits in the
> string than in the format.
> 
> # The part on the left of the decimal point.
> def sform_left( str, fmt )
>   result = ''
>   fmt = fmt.split(//)
>   str.split(//).reverse_each{|d|
>     while fmt.last != '0' do
>       result = fmt.pop + result
>     end
>     fmt.pop
>     result = d + result
>   }
>   result = fmt.first + result  if fmt.first != '0'
>   result
> end
> 
> # The part on the right of the decimal point.
> def sform_right( str, fmt )
>   ary = str.split(//)
>   fmt.gsub( /0/ ){ ary.shift || '0' }
> end
> 
> def sform( str, fmt )
>   str = str.split('.')
>   fmt = fmt.split('.')
>   result = sform_left( str[0], fmt[0])
>   if fmt[1]
>     result += "." + sform_right( str.last, fmt.last)
>   end
>   result
> end
> 
> puts sform("12345", "$00,000")
> puts sform("1234", "$00,000")
> puts sform("123", "$00,000")
> puts sform("12345.6", "$00,000.00")
> puts sform("12345.678", "$00,000.00")
> puts sform("12345.678", "$00,000")
> 
> --- output ---
> $12,345
> $1,234
> $123
> $12,345.60
> $12,345.67
> $12,345
> 
Thank you for the ideas.  I figured there had to be a better way to 
accomplish what I wanted without doing it like I would do it in C.  With 
a little work I think I can make these do everything I want to do.  The 
last step I need to work on is to allow it to handle formats that 
replace leading zeros with blanks.  This will allow the display of 
dollar amounts in neat columns.