From: William James <w_a_x_man@...>
Date: 2006-12-16T16:05:10+09:00
Subject: Re: matching lines....

Just Maz wrote:
> I'm really wracking my brain about this one though I bet there must be
> some simple command I don't know which I'm missing.
>
> I've got a file with a few lines:
> 1: Kevin 25 football cricket guitar
> 2: John 15 football karate
> 3: Fred 20 rugby painting
>
> Via regular expressions I'm trying to do a few things here such as
> counting how many hobbies people have and counting how many people have
> the same hobby- its this last one in particular I can't figure out.
>
> The only way I can think of is to split each line into a array (which in
> turn is stored in a array) and then have dual loops checking the 1st
> hobby from person 1 against the firsts of the others then against the
> seconds of the other and all but...This really does require a mountain
> of code and its proving very troublesome.
>
> Is there some special command in ruby I'm missing which could help me to
> do this quicker?
>
> --
> Posted via http://www.ruby-forum.com/.

hobbies = Hash.new{ [] }

ARGF.each{|line| n, name, age, *his_hobbies = line.split
  his_hobbies.each{|s| hobbies[s] += [ name ] } }

hobbies.sort_by{|k,v| [ -v.size, k] }.each{|k,v|
  printf "%-10s%s\n", k, v.join(", ") }