From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2010-07-30T16:33:12+09:00
Subject: Re: my script just read one line?

On Fri, Jul 30, 2010 at 1:58 AM, Junhui Liao <junhui.liao@uclouvain.be> wrote:
> Dear Jesús Gabriel y Galán and all,
>
>> File.open("../original_data/test_2lines.tsv").each_line do |record|
>>   a = record.chomp.split("\t")
>>   a.each_slice(2).with_index do |(time,signal), index|
>>     File.open("#{index}_debug_split"+".tsv" , "w") do |f|
>>       f << "#{time}\t#{signal}\n"
>>     end
>>   end
>> end
>
> This code ran well at 1.9.1 version of ruby. Since I tried at our
> server where ruby is this version.

BTW, I'm using 1.8.7. And also, File.open().each_line doesn't properly
close the file,
so we should be using File.foreach()

>
> Actually, I need to do this also: make the first line's time value
> subtracted by other lines' corresponding time ones.
>
> First line: time_1.1, signal_1.1, time_1.2, signal_1.2... time_1.4096,
> signal_1.4096.
> Second line: time_2.1, signal_2.1, time_2.2, signal_2.2... time_2.4096,
> signal_2.4096.
> .......
>
> I would like to do,  time_2.1 = time_2.1 - time_1.1 , time_2.2 =
> time_2.2 - time_1.2 ,
> ...... time_2.4096 = time_2.4096 - time_1.4096.
>                             ......
> Similar to other lines' time value.
>
> I tried to use a counter to pick up the first line (stupid way, I know)
> than save in an array, and
> take other lines time values to subtract this array, but failed. Since
> it seemed
> to the enumerator I could not access individual ? But "puts a[index] "
> printed two items
> (time and signal) well.  However, i could not print just time or signal
> value.

What I'd do is create an array for the first line with the times, and
use that after on to substract.
I've refactored a little bit to simplify (this is completely untested):

File.open("../original_data/test_2lines.tsv") do |file|
  first_line = file.readline
  first_line_times = first_line.chomp.split("\t").each_slice(2).map
{|time,signal| time}
  write_line_to_file first_line
  file.each_line do |record|
    line_data = record.chomp.split("\t")
      write_line_to_file line_data, first_line_times
  end
end

def write_line_to_file line, base_time = Hash.new(0)
  line_data.each_slice(2).with_index do |(time,signal), index|
    File.open("#{index}_debug_split"+".tsv" , "w") do |f|
      f << "#{time.to_i - base_time[index]}\t#{signal}\n"
    end
  end
end

Hope this gives you an idea to explore,

Jesus.