From: James Gray <james@...>
Date: 2008-09-24T21:53:07+09:00
Subject: Re: update a field in CSV file using fastercsv

On Sep 24, 2008, at 7:16 AM, Pit Capitain wrote:

> 2008/9/21 Gregory Brown <gregory.t.brown@gmail.com>:
>> The reason we need to do things this way is that (at least in Ruby,
>> but in most languages I'd imagine), there isn't really a way to  
>> make a
>> change to a file while you're reading it.
>
> Sorry, Greg, but that's not correct. See the following example.
>
> Create a file with three lines:
>
>  name = "test.txt"
>
>  File.open(name, "w") do |file|
>    3.times do |num|
>      file.puts "line #{num}"
>    end
>  end
>
> Check the contents of the file:
>
>  puts File.read(name)
>
> Output:
>
>  line 0
>  line 1
>  line 2
>
> Now read a line, write something, and read a line again:
>
>  File.open(name, "r+") do |file|
>    puts file.gets
>    file.puts "new data"
>    puts file.gets
>  end

This has pretty limited use.  It's rare that you can get away with  
chopping up a file like this, in my opinion.

James Edward Gray II