From: Stuart Clarke <stuart.clarke1986@...>
Date: 2008-12-22T01:25:52+09:00
Subject: Re: Using ruby hash on array

Thanks for your help Todd. I have gone for a different approach which I
will post should it work.

I was wondering could you explain this code:

 count.each do |a, cnt|
   printf "%20s %6d\n", a, cnt
 end


I have no idea what the %20s ...... is doing.

Many thanks

Todd Benson wrote:
> On Thu, Dec 18, 2008 at 1:12 PM, Stuart Clarke
> <stuart.clarke1986@gmail.com> wrote:
>> Sorry I was getting to replying to you then got called off in a hurry. I
>> do not understand some of the code you have used as I am relatively new
>> to Ruby. Can you briefly outline the code, it would be greatly
>> appreciated.
> 
>> Robert Klemme wrote earlier:
>> A framework:
>>
>> Data = Struct.new :a, :b:, :c, :d, :e, :f
> (leave off the extra : after b  :-)
> 
> Struct is an automatic way to define a simple class.  There, he's
> defining the structure of a class that he wants to call Data with the
> use of Struct.  So with this statement, we will have a class that has
> attributes a, b, c, d, e, f, all with getters and setters, and (at
> least in 1.8.7 AFAIK) an initialize method.  For example...
> 
> MySimpleClass = Struct.new :instance_var
> m = MySimpleClass.new "hi"
> puts m.instance_var
> m.instance_var = "bye"
> puts m.instance_var
> #hi
> #bye
> 
>>
>> def Data.parse(line)
>>   d = new(*line.strip.split(/\s+/))
>>   d.f = Integer(d.f)
>>   d
>> end
> 
> There he is defining a class method called parse on the class Data.
> This method returns a Data object filled with the info that was in the
> string "line".
> 
>>
>> count = Hash.new 0
> 
> As explained, that was a Hash initialization with a default value of 0
> 
>>
>> ARGF.each do |line|
>>   data = Data.parse(line)
>>   count[data.f[/Name:\t(.+?)\r\n/, 1]] += 1 if data.a == 100
>> end
> 
> Rack up the count if the conditions are met
> 
>>
>> count.each do |a, cnt|
>>   printf "%20s %6d\n", a, cnt
>> end
> 
> Print the darn thing out!
> 
> hth,
> Todd
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