From: Joel VanderWerf <vjoel@...>
Date: 2002-09-10T07:44:01+09:00
Subject: Re: How best to histogram words?

andrew queisser wrote:
> I want to count the occurrence of specific words. In the past I've
> used a hash as shown below. Is there a better way? I don't know which
> words will occur, otherwise I'd just preinitialize the hash to all
> zeros.
> 
> Thanks, Andrew
> 
> foo = Hash.new
> bar = Hash.new
> while l = gets
>   l.split.each { |w|
>     # option 1: try to increment cell, catch error
>     begin
>       foo[w] += 1
>     rescue NameError
>       foo[w] = 1
>     end
> 
>     # option 2: initialize on first use
>     bar[w] = 0 if !bar[w]
>     bar[w] += 1

Two other approaches to opt 2:

     bar[w] ||= 0
     bar[w] += 1

and

     bar[w] = bar[w].to_i + 1

>   }
> end
> puts foo
> puts bar