From: "David A. Black" <dblack@...>
Date: 2007-03-16T07:04:24+09:00
Subject: Re: Need help converting Perl to Ruby (detecting integers and decimals in strings)

Hi --

On 3/15/07, Paul <tester.paul@gmail.com> wrote:
> I am trying to convert a Perl script to Ruby and have been having some
> difficulty along the way (mostly because I don't know Perl).
>
> I am currently stumped on one particular line in the old Perl script:
> ---
>         foreach (@rawfields) {if ($_ > 0){$_ = int($_*100)/100}}
> ---
>
> Background context:  @rawfields is an array that holds the contents of
> an imported line from a text file.  Here are some sample lines from
> the input file:
> ---
> "0"     "0"     "0"     "0"     "0"     "0"     "Bar"
> "5.66666"       "0"     "3.566662"      "1.383332"      "6"     "0"     "Foo"
> ---
>
> My guess is that the Perl line iterates through each of the elements
> in the array and rounds any integers to 2 decimals.
>
> This raises a few problems for me.
>
> 1) How can I easily tell if the (string) value in each array element
> is an integer or has a decimal value?
>
> => The desired output for text file line 2 is :
> ---
> "5.67"   "0"   "3.57"   "1.38"   "6"   "0"   "Foo"
> ---
>
>
> I tried the following in Ruby:
> ---
> @rawfields.each_index do |x|
>         if ( @rawfields[x].to_f > 0 )
>                 @rawfields[x] = ( (( @rawfields[x].to_f * 100 ).round.to_i ).to_f /
> 100 ).to_s
>         end
> end
> ---
>
> But it produces the following output:
> ---
> "5.67"  "0"  "3.57"  "1.38"  "6.0"  "0"  "Foo"
> ---
>
> ...which is close, but not quite what I want.  My output file now has
> values like 1.0, 5.0, 62.0, etc.  If it's an integer, I don't want to
> see the decimal.
>
> Can anyone suggest an improvement to my code or a better translation
> from Perl?

See if this helps:

@rawfields.map! do |x|
  if x =~ /^\d+\.\d+$/
    "%.2f" % x
  else
    x
  end
end


David

-- 
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