Forum: Ruby sorting data from a file

Hey guys,

I have a txt file that contain the following data:

34,1,2,3,3,1,6,5
55,3,3,1,1,2,5,6
66,2,4,4,4,3,3,3
67,4,5,5,5,6,2,2
68,5,1,2,2,4,4,4
69,6,6,6,6,5,1,1

where the numbers in position [0] are integers. so basically, i wan to
sort the numbers from position [1..7] then pick the first four numbers
after sorting in each line.

any guidelines for how to do it.

P.S I'm still a beginner in programming..just doing my exam project.

Thank you for your help.

Hi,

what have you got so far? Are the lines in number arrays already?

I haven't done any thing yet.. i just didn't know where to start.
btw those numbers are not arrays. its the content of the file.

read
this: 
http://alvinalexander.com/blog/post/ruby/how-sort-...


I tried to do something very similar, and after reading Alvin's blog 
understood
exactly how to do it.

Wayne


----- Original Message ----
From: Ismail M. <lists@ruby-forum.com>
To: ruby-talk ML <ruby-talk@ruby-lang.org>
Sent: Wed, November 28, 2012 8:20:20 AM
Subject: sorting data from a file

Hey guys,

I have a txt file that contain the following data:

34,1,2,3,3,1,6,5
55,3,3,1,1,2,5,6
66,2,4,4,4,3,3,3
67,4,5,5,5,6,2,2
68,5,1,2,2,4,4,4
69,6,6,6,6,5,1,1

where the numbers in position [0] are integers. so basically, i wan to
sort the numbers from position [1..7] then pick the first four numbers
after sorting in each line.

any guidelines for how to do it.

P.S I'm still a beginner in programming..just doing my exam project.

Thank you for your help.

Ismail M. wrote in post #1086899:
> I haven't done any thing yet.. i just didn't know where to start.

What about parsing the file?

I mean, we can help you with specific questions. But don't expect us to
drag you to the solution or hand it out for you to copy and paste. You
should at least have a vague idea of what is necessary to complete the
task.

The first thing is obviously to open/read the file. Can you do that?



Ismail M. wrote in post #1086899:
> btw those numbers are not arrays. its the content of the file.

I do know that, but I was asking if you've already done the first step
(no).

On Wed, Nov 28, 2012 at 2:47 PM, Ismail M. <lists@ruby-forum.com> wrote:
> I haven't done any thing yet.. i just didn't know where to start.
> btw those numbers are not arrays. its the content of the file.

Documentation for Ruby is here

http://www.ruby-doc.org/core-1.9.3/

You're going to need to look at things like "File", possibly "Regexp",
"Array", "String".

Alan

How do I unsubscribe?

Travis

of course I see your point Jan E.

I opened/read the file and displayed in on ruby command promt.

then i thought of a way to sort the data in the file.


l = [1,2,3,3,1,6,5]

smallest = l.sort.first 4

=> [1,1,2,3]

however applying this method in my case is the problem. How do i connect 
this method to my file then make a loop than sort each line in my file.

Read the blog entry I sent earlier. It will all make sense once you read 
it
(you're going to want to store things into two different "fields" or 
objects
stored in an array)... or start thinking about hashes.

Wayne


----- Original Message ----
From: Ismail M. <lists@ruby-forum.com>
To: ruby-talk ML <ruby-talk@ruby-lang.org>
Sent: Wed, November 28, 2012 9:36:56 AM
Subject: Re: sorting data from a file

of course I see your point Jan E.

I opened/read the file and displayed in on ruby command promt.

then i thought of a way to sort the data in the file.


l = [1,2,3,3,1,6,5]

smallest = l.sort.first 4

=> [1,1,2,3]

however applying this method in my case is the problem. How do i connect
this method to my file then make a loop than sort each line in my file.

On Wed, Nov 28, 2012 at 3:36 PM, Ismail M. <lists@ruby-forum.com> wrote:
>
> => [1,1,2,3]
>
> however applying this method in my case is the problem. How do i connect
> this method to my file then make a loop than sort each line in my file.

Write a script "script.rb" and run it from the command line by typing
"ruby script.rb".

In your script, read the file into an array using
myarray = IO.readlines("myfile.txt")

Then you have to think about the elements of the array and look at the
documentation to work out the rest.

Alan

Alan Forrester wrote in post #1086915:
>
> In your script, read the file into an array using
> myarray = IO.readlines("myfile.txt")
>

Why would you suggest that?  What's the matter with the method:

  IO.foreach(fname) {|line| #code here}

> You're going to need to look at things like "File", possibly
> "Regexp",

No, File is unnecessary--even in your example, and the op said they are 
a beginner, so
needlessly complicating the code with regexes is bad advice. 
String#split() is more than adequate.

On 28 Nov 2012, at 19:15, 7stud -- <lists@ruby-forum.com> wrote:

> Alan Forrester wrote in post #1086915:
>>
>> In your script, read the file into an array using
>> myarray = IO.readlines("myfile.txt")
>>
>
> Why would you suggest that?  What's the matter with the method:
>
>  IO.foreach(fname) {|line| #code here}


I think the problem for somebody who knows very little Ruby will be 
filling in the "code here" part of that prescription without ever 
looking the object to which he is applying the code.

Alan

You can argue all day long about which solution is easier to understand 
and better for a beginner. But personally, I'm more interested in which 
methods *he* knows. If he knows File.readlines, that's fine. Then we can 
use it. If he knows File.foreach, that's fine, too.

I know Ruby programmers love endless discussions about the best 
solution. But it would be great if maybe this time you could not do that 
and just help.


@ Ismail:

Please write down everything that you currently have (ideas, code, 
whatever). Your code snippet for the smallest number is already useful. 
You'll be able to use that later.

It's beginner question. My advice is that you go through some beginners
tutorial about Ruby. After that you will know to implement it. Here is 
your
starting code:
require 'csv'

class ParseCSV
 def initialize
@csv = CSV.read "data.csv"
 end
 def test
@csv[0] # it's first row
 end
end

pc = ParseCSV.new
pc.test

As you see it's easier to process your data by csv class, since it's in
comma separaterd values format. In constructor you initialize @csv 
variable
which is 2 dimensional array. You acces it through indexes. For example 
to
get 1st cell, then you type @csv[0][0]. You get first row by @csv[0].

If you want to go through all rows then you type:
@csv.each do |row|



2012/11/28 Jan E. <lists@ruby-forum.com>

If you want to go through all rows then you type:
@csv.each do |row|
  # do something with row
end

Hello everybody!
i have a txt file which contains numbers as mentioned earlier..then i 
made a method that shows the ranking rules.

def majority()
    @majority = @rank[3]
    if @rank[3] == @rank[4] then
      @majority = @rank[4]
    end
    if @rank[4] == @rank[5] then
      @majority = [5]
    end
    if @rank[5] == @rank[6] then
      @majority = @rank[6]
    end

so, how do i sort that file by the ones who has the lowest value of 
@majority. i thought about using sort_by method..but i dont know how to 
use it in my case.