sw@debian:~/sandbox$ irb
1.9.3p194 :001:0> a = [1,2,3,4,5]
=> [1, 2, 3, 4, 5]
1.9.3p194 :002:0> a.class
=> Array
1.9.3p194 :003:0> exit

sw@debian:~/sandbox$ irb
1.9.3p194 :001:0> a = ['Test', 'Apfelbaum', 'blau']
=> ["Test", "Apfelbaum", "blau"]
1.9.3p194 :002:0> a.class
=> Array
1.9.3p194 :003:0> a[1]
=> "Apfelbaum"
1.9.3p194 :004:0> a[1].class
=> String
1.9.3p194 :005:0> exit

sw@debian:~/sandbox$ irb
1.9.3p194 :001:0> a = [1, 2, 'Haus', 'Baum', 4]
=> [1, 2, "Haus", "Baum", 4]
1.9.3p194 :002:0> a.class
=> Array
1.9.3p194 :003:0> a[0]
=> 1
1.9.3p194 :004:0> a[0].class
=> Fixnum
1.9.3p194 :005:0> a[2]
=> "Haus"
1.9.3p194 :006:0> a[2].class
=> String
1.9.3p194 :007:0> exit

sw@debian:~/sandbox$ ri Array
= Array < Object

------------------------------------------------------------------------------
= Includes:
Enumerable (from ruby site)

(from ruby site)
------------------------------------------------------------------------------
Arrays are ordered, integer-indexed collections of any object. Array indexing
starts at 0, as in C or Java.  A negative index is assumed to be relative to
the end of the array---that is, an index of -1 indicates the last element of
the array, -2 is the next to last element in the array, and so on.

------------------------------------------------------------------------------
= Class methods:

  [], new, try_convert

= Instance methods:
  &, *, +, -, <<, <=>, ==, [], []=, abbrev, assoc, at, clear, collect,
  collect!, combination, compact, compact!, concat, count, cycle, dclone,
  delete, delete_at, delete_if, drop, drop_while, each, each_index, empty?,
  eql?, fetch, fill, find_index, first, flatten, flatten!, frozen?, hash,
  include?, index, initialize_copy, insert, inspect, join, keep_if, last,
  length, map, map!, pack, permutation, pop, pretty_print, pretty_print_cycle,
  product, push, rassoc, reject, reject!, repeated_combination,
  repeated_permutation, replace, reverse, reverse!, reverse_each, rindex,
  rotate, rotate!, sample, select, select!, shelljoin, shift, shuffle,
  shuffle!, size, slice, slice!, sort, sort!, sort_by!, take, take_while,
  to_a, to_ary, to_csv, to_s, transpose, uniq, uniq!, unshift, values_at, zip,
  |

sw@debian:~/sandbox$ 

sw@debian:~/sandbox$ irb
1.9.3p194 :001:0> a = Array.new
=> []
1.9.3p194 :002:0> a.class
=> Array
1.9.3p194 :003:0> a << 'erster Eintrag'
=> ["erster Eintrag"]
1.9.3p194 :004:0> a << 'zweiter Eintrag'
=> ["erster Eintrag", "zweiter Eintrag"]
1.9.3p194 :005:0> a << 'dritter Eintrag'
=> ["erster Eintrag", "zweiter Eintrag", "dritter Eintrag"]
1.9.3p194 :006:0> a.size
=> 3
1.9.3p194 :007:0> exit

sw@debian:~/sandbox$ irb
1.9.3p194 :001:0> class Tier              # Definition einer Klasse Tier
1.9.3p194 :002:1>   def initialize(de_name,en_name)
1.9.3p194 :003:2>     @de_name = de_name
1.9.3p194 :004:2>     @en_name = en_name
1.9.3p194 :005:2>   end
1.9.3p194 :006:1>   def to_s
1.9.3p194 :007:2>     @de_name + ' (' + @en_name + ')'
1.9.3p194 :008:2>   end
1.9.3p194 :009:1> end
=> nil
1.9.3p194 :010:0> lumpi = Tier.new('Hund', 'Dog')
=> #<Tier:0x873b5c8 @de_name="Hund", @en_name="Dog">
1.9.3p194 :011:0> hansi = Tier.new('Wellensittich', 'Budgerigar')           
=> #<Tier:0x86b60f8 @de_name="Wellensittich", @en_name="Budgerigar">
1.9.3p194 :012:0> haustiere = Array.new   # haustiere ist ein Array
=> []
1.9.3p194 :013:0> haustiere << hansi      # hansi wird hinzugefuegt
=> [#<Tier:0x8d11f18 @de_name="Wellensittich", @en_name="Budgerigar">]
1.9.3p194 :014:0> haustiere << lumpi      # lumpi wird hinzugefuegt
=> [#<Tier:0x8d11f18 @de_name="Wellensittich", @en_name="Budgerigar">, #<Tier:0x8d9751c @de_name="Hund", @en_name="Dog">]
1.9.3p194 :015:0> haustiere.count
=> 2
1.9.3p194 :016:0> puts haustiere[1]       # Ausgabe der Position 1
Hund (Dog)
=> nil
1.9.3p194 :017:0> puts haustiere[0]       # Ausgabe der Position 0
Wellensittich (Budgerigar)
=> nil
1.9.3p194 :018:0> exit

sw@debian:~/sandbox$ irb
1.9.3p194 :001:0> preisliste = { '6 Eier' => 1.2, '12 Eier' => 2, '500 gr Butter' => 0.99 }
=> {"6 Eier"=>1.2, "12 Eier"=>2, "500 gr Butter"=>0.99}
1.9.3p194 :002:0> preisliste['12 Eier']
=> 2
1.9.3p194 :003:0> preisliste.count
=> 3
1.9.3p194 :004:0> exit

sw@debian:~/sandbox$ ri Hash
= Hash < Object

------------------------------------------------------------------------------
= Includes:
Enumerable (from ruby site)

(from ruby site)
------------------------------------------------------------------------------
A Hash is a collection of key-value pairs. It is similar to an Array, except
that indexing is done via arbitrary keys of any object type, not an integer
index. Hashes enumerate their values in the order that the corresponding keys
were inserted.

Hashes have a default value that is returned when
accessing keys that do not exist in the hash. By default, that value is nil.

------------------------------------------------------------------------------
= Class methods:

  [], new, try_convert

= Instance methods:
  ==, [], []=, assoc, clear, compare_by_identity, compare_by_identity?,
  default, default=, default_proc, default_proc=, delete, delete_if, each,
  each_key, each_pair, each_value, empty?, eql?, fetch, flatten, has_key?,
  has_value?, hash, include?, initialize_copy, inspect, invert, keep_if, key,
  key?, keys, length, member?, merge, merge!, pretty_print,
  pretty_print_cycle, rassoc, rehash, reject, reject!, replace, select,
  select!, shift, size, store, to_a, to_hash, to_s, update, value?, values,
  values_at

sw@debian:~/sandbox$