Creating new arrays from existing arrays in Ruby

You can do it in one line just use group_by and with_index:

grouped = values.group_by.with_index {|_, i| fields[i] }
#=> {"name"=>["Patrick Ewing", "Rik Smits", "Bill Russell"],'
    "team"=>["New York Knicks", "Indiana Pacers", "Boston Celtics"],            
    "number"=>[33, 45, 6]}

Then you can simple produce your arrays from this hash:

name = grouped["name"]
#=> ["Patrick Ewing", "Rik Smits", "Bill Russell"]

Or just:

names, teams, numbers = grouped.values

If the input is consistently in groups of three you can use each_slice:

values = ["Patrick Ewing", "New York Knicks", 33, "Rik Smits", "Indiana Pacers", 45, "Bill Russell", "Boston Celtics", 6]

names = [ ]
teams = [ ]
numbers = [ ]

values.each_slice(3) do |name, team, number|
  names << name
  teams << team
  numbers << number
end

That's not the most optimal way of organizing things. A more Ruby-oriented style would be:

keys = [ :name, :team, :number ]

players = values.each_slice(3).collect do |set|
  Hash[keys.zip(set)]
end
#=> [{:name=>"Patrick Ewing", :team=>"New York Knicks", :number=>33}, {:name=>"Rik Smits", :team=>"Indiana Pacers", :number=>45}, {:name=>"Bill Russell", :team=>"Boston Celtics", :number=>6}]

That gives you easy access to each record without having to cross-reference multiple arrays. Even if you're displaying this in a table and need the three things separately you can still do this to select out an individual value:

keys.each do |key|
  players.each do |player|
    print '%-20s' % player[key]
  end

  puts
end

That gives you output like:

Patrick Ewing       Rik Smits           Bill Russell        
New York Knicks     Indiana Pacers      Boston Celtics      
33                  45                  6                   

Yet another way: using Facets Enumerable#map_by:

require 'facets'
names, teams, numbers = fields.zip(values).
  map_by { |field, value| [field, value] }.
  values_at("name", "team", "number")

Here is one way to group the array values by their "type":

fields = ["name", "team", "number", "name", "team", "number", "name", "team", "number"]
values = ["Patrick Ewing", "New York Knicks", 33, "Rik Smits", "Indiana Pacers", 45, "Bill Russell", "Boston Celtics", 6]

field_values = fields.zip(values)

names = field_values.select { |f, v| f == "name" }.map(&:last)
# => ["Patrick Ewing", "Rik Smits", "Bill Russell"]

teams = field_values.select { |f, v| f == "team" }.map(&:last)
# => ["New York Knicks", "Indiana Pacers", "Boston Celtics"]

numbers = field_values.select { |f, v| f == "number" }.map(&:last)
# => [33, 45, 6]