From: dblack@...
Date: 2007-07-06T08:12:26+09:00
Subject: Re: how to convert string into number

Hi --

On Fri, 6 Jul 2007, Guest wrote:

> Hi all,
>
> I read several rows of numbers and split each row into an array. I get
> an array of array. By default Ruby treat each number as a string. I want
> to convert each string into a number. The only way I can think of is to
> loop through the old array of array, change each element in each row
> using #to_f and put them back into a new array.  It is not efficient.
> What other options might be better?
>
> Thanks,
>
> Li
>
> # file format
>
> 1 100 33 32
> 2 500 33 20

You could do:

require 'scanf'
File.open("filename") do |fh|
   fh.scanf("%f%f%f%f") {|n| n }
end

The point of the {|n| n} is to force a capture of each set of numbers,
using the block form of scanf.  If you're not sure how many numbers
are on each line, you'd have to do a little more work but scanf might
still be a good option.


David

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