From: Mikael Larsson <per.mikael.larsson@...>
Date: 2002-02-24T20:20:13+09:00
Subject: Re: Newbie question

Hi!

This is a even a more newbie*newbie question.
what does the "p" stands for?
 >  # Based on same tsd.txt file as last time:
 >  t = TSDB.new("tsd.txt")
 >  p t[1]["field1"]        # "one"
 >  p t[2]["field2"]        # "orange"
Is it a short name for "puts" or what?

Mike

----- Original Message ----- 
From: "David Alan Black" <dblack@candle.superlink.net>
To: "ruby-talk ML" <ruby-talk@ruby-lang.org>
Sent: Sunday, February 24, 2002 3:27 AM
Subject: Re: Newbie question


> Hello --
> 
> On Sun, 24 Feb 2002, roktas wrote:
> 
> > $FMT = "/\t/"
> >
> > # Only one hash for the field labels (not 2*n)
> > $labels = {}
> >
> > def parse_line(line, fmt=$FMT)
> >     # No extra process for the present
> >     line.chomp.strip(delim)
> > end
> >
> > def DB
> >     def initialize(f)
> >         # First create the $labels hash from the first line
> >         $labels = ...
> >
> >         # Other stuff filling the @tab array
> >         ...
> >     end
> >
> >     ...
> >
> >     def [](key)
> >         @tab[key]
> >     end
> > end
> >
> > def Record < Array
> >     def initialize(line)
> >         # Parse and create a new record
> >         parse_line(line)
> >     end
> >     def [](key)
> >         key if key.kind_of?Integer
> >         $labels.index(key) if key.kind_of?String
> >         # Raise something for invalid cases ?
> >     end
> > end
> >
> > Well... (1) I don't want to use any global var ($labels), (2) Seperating
> > 'records' and 'whole database' (DB) would be fine.
> 
> I'm not sure about (2).  Somehow the Record has to know about the
> fields in the database.  Here's one way to do it with relatively
> little overhead -- each Record has an instance variable which points
> to the relevant fields array (but doesn't duplicate that array).
> 
> 
>   class TSDB < Array
>     attr_reader :labels, :records
>     SEP = "\t"
> 
>     def TSDB.parse_line(line, sep=SEP)
>       line.chomp.strip.split(/#{sep}/)
>     end
> 
>     class Record < Array
>       attr_accessor :fields
> 
>       def initialize(line)
> concat(TSDB.parse_line(line))
>       end
> 
>       def [](key)
> at(@fields.index(key))
>       end
>     end
> 
>     def initialize(f)
>       fh = File.open(f, "r")
>       @fields = TSDB.parse_line(fh.readline)
>       push("Dummy 0th record")
>       concat (fh.readlines.map do |line|
>   r = Record.new(line)
>   r.fields = @fields
>   r
>       end)
>     end
>   end
> 
>   # Based on same tsd.txt file as last time:
>   t = TSDB.new("tsd.txt")
>   p t[1]["field1"]        # "one"
>   p t[2]["field2"]        # "orange"
> 
> 
> 
> David
> 
> -- 
> David Alan Black
> home: dblack@candle.superlink.net
> work: blackdav@shu.edu
> Web:  http://pirate.shu.edu/~blackdav
>