2007/3/9, Kev <griffin.kev / gmail.com>:
> On 9 Mar, 09:12, "Kev" <griffin.... / gmail.com> wrote:
> > Hello,
> >
> >   I am writing a class and I require it to open a file, and store the
> > contents in key, value pairs.
> > This is my first
> >
> >   def initialize()
> >     @@store = Hash.new
> >   end
> >
> >   def read_file
> >     if File.exists?("LocationCopy.csv")
> >       f = File.open("LocationCopy.csv","r")
> >       f.each do |line|
> >         temp = line.split(",")
> >         @@store[temp[0]] = temp[1]
> >       end
> >       f.close
> >     end
> >     #puts @@store
> >   end
>
> Unfortunately thats what I call finger trouble, as I was saying this
> is my first attempt at a Ruby application and was wondering if there
> is a more efficient method for what I am trying to achieve. Would
> using f.each_line and using a block be better?

Efficiency is ok.  Using the block form of File.open is safer, i.e.
the file is always closed - even in case of error. But you should not
use a class variable, use @store instead.

And you can make your life easier by using CSV lib.  Then it becomes a
one liner:

10:41:07 [~]: cat x
a,b
d,b;c

10:41:08 [~]: ruby -r csv -r enumerator -e 'p CSV.to_enum(:open, "x",
"r", ";").inject({}) {|h,(k,v)| h[k]=v; h}'
{"a,b"=>nil, "d,b"=>"c"}

10:41:32 [~]: ruby -r csv -r enumerator -e 'p CSV.to_enum(:open, "x",
"r", ",").inject({}) {|h,(k,v)| h[k]=v; h}'
{"a"=>"b", "d"=>"b;c"}

CSV.foreach uses "," as default separator:

10:41:49 [~]: ruby -r csv -r enumerator -e 'p CSV.to_enum(:foreach,
"x").inject({}) {|h,(k,v)| h[k]=v; h}'
{"a"=>"b", "d"=>"b;c"}

Explanation: CSV.foreach yiels every record to the block.  By using
to_enum (which is part of "enumerator") you can treat the CSV reader
like any Enumerable.  With #inhect, a value is passed as first
parameter to the block and the block result is passed to the next
invocation to the block. In this case the hash which is stuffed into
#inject is simply passed on and on and is ultimately the result of
#inject. "p" then prints it.

Kind regards

robert

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