From: Sean O'Dell <sean@...>
Date: 2004-06-22T03:41:08+09:00
Subject: Re: newbie problem with a hash

On Monday 21 June 2004 11:08, Graham Nicholls wrote:
> I've got a file which I've read in and split to make a hash like this:
>
>
> def initialize(fname)
>   @data=Hash.new
>   begin
>   IO.foreach(fname) do |line|
>     key,value=line.chomp.split(":")
>     @data[key]=value
>   end
> end
>
> This gives a hash keyed on the first field of the file, where : is the
> separator.            (NB How do I handle : in the data - prompt to self!)
>
> But when I try to get the value associated with that key by a fetch, I get
> and IndexError:
>
> def get_datum(datid) # Typical datid is $01 - I've stripped off the colon.
>  if $debug
>    print("Getting data for id [#{datid}]\n") # Prints $01
>  end
>
>  begin
>   #@data.fetch("$01") - this works OK,
>   @data.fetch(datid)    # This causes an IndexError
>   rescue IndexError => err
>     print("No data for key [#{datid}] : #{err}\n")
>     @data.each do |key,val|
>             printf("Key [%s] => [%s]\n",key,val) # Shows $01 => avalue
> (amongst others)
>     end
>     exit(NO_DATA)
>  end
> end
>
> I'm racking my brains, but to no avail.  If I put the key in as a literal,
> it returns, but using the datid variable, I get an IndexError.

How are you calling get_datum?  Show us the line where you call it that gives 
you that error.

	Sean O'Dell