[ruby-talk:7990] Re: beginner's question -- hashes

Thanks very much, David. I wasn't sure if I had some silly syntax error.
Unfortunately I accidentally saved something else (the console window in
rubywin) over my code so I wasn't able to figure out what my error was. I
tried to recreate it but this time it all worked according to plan. Funny,
I was disappointed when it worked.

At the end of this message, after the quoted stuff, I have appended the
first program written by my 13 year old son, (which does essentially the
same thing I was trying to do.) I'm not sure if such inclusion is
appropriate for this list/group but I'm so proud of him I can't help
myself. It uses the free cue-cat scanner you can get from radio shack. You
scan bar-codes into a hash as keys and associate them with names. Not
particularly useful but it sure has been a big victory for him.

John

On Fri, 22 Dec 2000, David Alan Black wrote:

> Hello --
> 
> On Fri, 22 Dec 2000, John Rubinubi wrote:
> 
> > when I loop through the following...
> > 
> > st=gets.chop!
> > if not hash[st] #I suppose I should use has_key?
> >   hash[st]='some_value'
> > else
> >   puts hash[st]
> > end
> > 
> > 
> > when I go through the loop again and enter the same key it doesn't find it
> > although the same code finds the key-value pairs that I put in the hash
> > with a literal when I created it. 
> 
> I can't duplicate your problem:
> 
>    hash = {}
>    loop do
>      st=gets.chop!
>      if not hash[st]
>        hash[st]='some_value'
>      else
>        puts hash[st]
>      end
>    end
> 
> run:
> 
>    a
>    b
>    a
>    some_value
>    b
>    some_value
> 
> 
> David
> 
> -- 
> David Alan Black
> home: [e-mail]
> work: [e-mail]
> Web:  http://pirate.shu.edu/~blackdav
> 
> 
#by: Jesse
scan={}
done=false
while not done
  puts "scan an item, enter q to quit, or p to print your items"
  g=gets.chop!
  if g=='q'
    done=true
  elsif g=='p'
    scan.each_value {|value| puts value }
  elsif not scan.key?(g)
    puts 'new item -- enter name'
    ge=gets.chop!
    scan2={g=>ge}
    scan.update(scan2) 
  else
    puts scan[g]
  end
end
puts"\nHasta Luego!!"