CodeKeep Ruby Feed

Numerical Arrays in Ruby

Fri, 02 Jan 2009 06:50:06 GMT

Description: This code demonstrates the addition of numerical array capability to Ruby similar to what can be achieved via numpy.

Link: http://www.codekeep.net/snippets/6cae6dc5-031b-4efd-afe4-63b5266303d9.aspx

#!/usr/bin/env ruby -w -KU
# numarray.rb
$KCODE="UTF-8"
=begin
This module demonstrates a numerical array similar to Numpy in
Python or some of the things you can do in MATLAB.

Author: Michael O'Keefe
Date: December 1, 2008
http://www.okeefecreations.com
=end


module NumArray
    def map_elements(&block)
        tail.zip(init).map(&block)
    end
  
    def diff
        map_elements { | x | x[0] - x[1] }
    end

    def average
        map_elements { | x | 0.5 * (x[0] + x[1]) }
    end

    def plus(other)
        zip(other).map { | x | x[0] + x[1] }
    end

    def minus(other)
        zip(other).map { | x | x[0] - x[1] }
    end

    def times(other)
        zip(other).map { | x | x[0] * x[1] }
    end

    def divide(other)
        zip(other).map do | x |
            if x[1] != 0.0 then
                x[0] / x[1]
            else
                0.0
            end
        end
    end

    def pow(n)
        map { | x | x ** n }
    end

    def increasing?
        tail.zip(init).all? { | x | x[0] > x[1] }
    end
    
    def decreasing?
        tail.zip(init).all? { | x | x[0] < x[1] }
    end

    def cubed_avg
        map_elements do | x |
            x0 = x[0]
            x1 = x[1]
            (x0 ** 3 + x0 ** 2 * x1 + x0 * x1 ** 2 + x1 ** 3) / 4.0
        end
    end

    def squared_avg
        map_elements do | x |
            x0 = x[0]
            x1 = x[1]
            (x0 ** 2 + x0 * x1 + x1 ** 2) / 3.0
        end
    end

    def tail
        self[1..-1]
    end

    def init
        self[0..-2]
    end

    def head
        self[0]
    end

    def last
        self[-1]
    end
end


class Array
  include NumArray
end

#----------------------------------------------
#!/usr/bin/env ruby -w -KU
# testnumarray.rb
$KCODE="UTF-8"
=begin
This is a unit test module for numarray.rb

Author: Michael O'Keefe
Date: December 1, 2008
http://www.okeefecreations.com
=end
require 'test/unit'
require 'numarray'


class TestNumArray < Test::Unit::TestCase
    def setup
        @a1 = [1.0, 2.0, 3.0, 4.0, 5.0]
        @a2 = [10.0, 20.0, 30.0, 40.0, 50.0]
        @a3 = [2.0, 2.0, 2.0, 2.0]
    end
    
    def test_diff
        assert_equal(@a1.diff,
            [1.0, 1.0, 1.0, 1.0]
        )
    end
    
    def test_average
        assert_equal(@a1.average,
            [1.5, 2.5, 3.5, 4.5]
        )
    end
    
    def test_plus
        assert_equal(@a1.plus(@a2),
            [11.0, 22.0, 33.0, 44.0, 55.0]
        )
    end
    
    def test_minus
        assert_equal(@a1.minus(@a2),
            [-9.0, -18.0, -27.0, -36.0, -45.0]
        )
    end
    
    def test_times
        assert_equal(@a1.times(@a2),
            [10.0, 40.0, 90.0, 160.0, 250.0]
        )
    end
    
    def test_divide
        assert_equal(@a1.divide(@a2),
            [0.1, 0.1, 0.1, 0.1, 0.1]
        )
    end
    
    def test_pow
        assert_equal(@a1.pow(2),
            [1.0, 4.0, 9.0, 16.0, 25.0]
        )
    end
    
    def test_increasing?
        assert_equal(@a1.increasing?, true)
    end
    
    def test_decreasing?
        assert_equal(@a1.decreasing?, false)
    end

    def test_cubed_avg
        assert_equal(@a3.cubed_avg, [8.0, 8.0, 8.0])
    end

    def test_squared_avg
        assert_equal(@a3.squared_avg, [4.0, 4.0, 4.0])
    end
    
    def test_tail
        assert_equal(@a1.tail, [2.0, 3.0, 4.0, 5.0])
    end
    
    def test_init
        assert_equal(@a1.init, [1.0, 2.0, 3.0, 4.0])
    end
    
    def test_head
        assert_equal(@a1.head, 1.0)
    end
    
    def test_last
        assert_equal(@a1.last, 5.0)
    end
end

M�dulo Ruby con constantes �tiles.

Fri, 25 May 2007 16:16:29 GMT

Description: Es un m�dulo en Ruby que define constantes globales de una aplicaci�n. En el momento solamente define la expresi�n regular utilizada para validar un email.

Link: http://www.codekeep.net/snippets/3b2495b9-d38e-4283-8cd8-2632e2163793.aspx

module Utilidades::Constantes
  # Establecer la expresión regular para validar los email
  EXPREG_EMAIL = /^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$/i
end

Clase que genera aleatorios

Wed, 07 Mar 2007 14:52:12 GMT

Description: Esta es una clase en Ruby que genera aleatorios

Link: http://www.codekeep.net/snippets/1f074d22-e770-4d15-b40b-bf61bd994569.aspx

class Utilidades::GeneradorAleatorio

  # genera una palabra aleatoria con la cantidad de caracteres especificada
  # utiliza las letras de la 'a' a la 'z' minúsculas y masyúsculas y los números del '0' al '9'
  def self.generar_palabra(cantidad = 10)
    return self.generar(cantidad) { ("a".."z").to_a + ("A".."Z").to_a + ("0".."9").to_a }
  end
  
  # genera una número aleatorio con la cantidad de dígitos especificada
  # utiliza los números del '0' al '9'
  def self.generar_numero(cantidad = 10)
    return self.generar(cantidad) { ("0".."9").to_a }
  end
  
  # genera una cadena de caracteres aleatoria
  # debe proveerse un bloque que retorne un arreglo de donde se sacarán los caracteres
  def self.generar(cantidad = 10)
    chars = yield
    random_key = ""
    1.upto(cantidad) { |i| random_key << chars[rand(chars.size)] }
    return random_key
  end
end

Multi-select list boxes in Rails

Wed, 14 Feb 2007 16:48:04 GMT

Description: Muestra como crear una lista selecci�n m�ltiple y como obtener los valores luego en el controlador.

Link: http://www.codekeep.net/snippets/73bffc67-991b-4231-a2ee-fdce2fdb5a26.aspx

# para contruir la lista en la vista
<%= select_tag 'flavors[]',  
  options_for_select( 
    [['vanilla','1'], ['strawberry','2'], ['chocolate','3']] ),
  { :multiple => true, :size =>5 } 
%>

# para obtener los valores en el controlador
@sunday = IceCreamSunday.create(params[:sunday])    
unless has_errors?(@sunday)
  @sunday.flavors << Flavor.find(params[:flavors].collect{|char| char.to_i})
  redirect_to make_the_dish_url(:id => @sunday.id)
end

Create a random password

Tue, 14 Feb 2006 12:29:16 GMT

Description: Creates a random password using numbers and letters

Link: http://www.codekeep.net/snippets/e41fb216-7061-41b0-8612-2c258d51ef68.aspx

private
def newpass( len )
  chars = ("a".."z").to_a + ("1".."9").to_a
  newpass = ""
  1.upto(len) { |i| newpass << chars[rand(chars.size-1)] }
  return newpass
end

Hash Password

Tue, 14 Feb 2006 12:26:41 GMT

Description: Hashes a password using SHA1

Link: http://www.codekeep.net/snippets/5d3afb89-c35d-40c4-b906-520f2ed817c6.aspx

def self.hash_password(pass)
  Digest::SHA1.hexdigest(pass)
end