OnRails.org

 
1.class.ancestors
=> [Fixnum, Integer, Numeric, Comparable, Object, Kernel, BasicObject]

1.class.instance_methods(false)
=> [:to_s, :-@, :+, :-, :*, :/, :div, :%, :modulo, :divmod, :fdiv, :**, :abs, :magnitude, :==, :<=>, :>, :>=, :<, :<=, :~, :&, :|, :^, :[], :<<, :>>, :to_f, :size, :zero?, :odd?, :even?, :succ]

m = 1.method(:inspect)
=> #<Method: Fixnum(Kernel)#inspect>

require 'benchmark'
puts Benchmark.measure {(1..1000000).map{|num| ""+num.to_s}}
  0.940000   0.050000   0.990000 (  1.001714)

puts Benchmark.measure {(1..1000000).map{|num| ""+num.to_s}}
  1.800000   0.050000   1.850000 (  1.850319)

require 'benchmark'
Benchmark.bm do |b|
  b.report("map") {(1..1000000).map{|num| ""+num.to_s}}
  b.report("inject") {(1..1000000).inject(""){|accum, num| ""+num.to_s}}
end
      user     system      total        real
map  1.970000   0.070000   2.040000 (  2.077786)
inject  1.910000   0.010000   1.920000 (  1.978541)

require 'dl/import'
require 'dl/struct'

def fib(n)
 @k||={}
 n<=2 ? 1 : (@k[n-1]||=fib(n-1))+(@k[n-2]||=fib(n-2))
end

puts fib(200)
280571172992510140037611932413038677189525

Program exited with code #0 after 0.02 seconds

def fib(n)
  if n <= 2 
      1
  else
     fib(n-1) + fib(n-2)
  end
end

alias :pre_memoized_fib :fib

def fib(n)
  @cache ||= {}
  @cache[n] ||= pre_memoized_fib(n)
end

class << str   # << opens up the singleton class. Arrows seem to go wrong way.
  p self  # ghost class: <Class:#<String:0x1d0ec>> - class of the class String
  def speak
    puts "miaow"
  end
end

puts str.speak

class Dave
  class << self   # puts the methods into the singleton class and becomes class methods
    def do_something      
    end
  end
end

class Person < Struct.new(:name, :age)
  def greet
      puts "Hello #{self.name}"
  end
end

f = Person.new("Chad", 28)

module Logger
  def log(msg)
    puts msg
  end
end

class Album
  include Logger
end


Album.ancestors # => [Album, Logger, Object, Kernel]
# Note that Logger becomes ancestor of Album...It's insert a generated class named after the module that shares the method table.

module Speak
  def hello
     puts "hello"
  end
end

str = "cat"
str.extend Speak

puts str.hello

 
$/usr/local/ruby1.9/bin/ruby -v 
ruby 1.9.1p0 (2009-01-30 revision 21907) [i386-darwin9.6.0]
$/usr/local/ruby1.9/bin/irb 
RUBY_VERSION 
=> "1.9.1"

class Scribbish < TypoTheme
  include JamesWilfordCSS
end

#!/usr/bin/env ruby

require 'optparse'

OPTIONS = { :Verbose => false,
            :Force => false,
            :DownloadDir => '.',
            :DescriptiveFilenames => true
          }
OptionParser.new do |opts|
  opts.banner = "Usage: #{$0} [options]"

  opts.on("-v", "--[no-]verbose", "Run verbosely, default #{OPTIONS[:Verbose]}") do |verbose|
    OPTIONS[:Verbose] = verbose
  end
  opts.on("-f", "--[no-]force", "Force downloads, default #{OPTIONS[:Force]}") do |force|
    OPTIONS[:Force] = force
  end
  opts.on("-d", "--[no-]descriptive", "Use long descriptive filenames, default #{OPTIONS[:DescriptiveFilenames]}") do |long|
    OPTIONS[:DescriptiveFilenames] = long
  end
  opts.on("-p", "--path PATH", "Path to download to, default #{OPTIONS[:DownloadDir]}") do |path|
    OPTIONS[:DownloadDir] = path
  end
  opts.on_tail("-h", "--help", "Print help message") do |help|
    puts opts
    exit
  end
end.parse!

require 'rubygems'
require 'hpricot'
require 'open-uri'
require 'fileutils'

BASE_URL = 'http://www.web2expo.com'

def log(str)
  puts str if OPTIONS[:Verbose]
end

def download(href, filename)
  url = "#{BASE_URL}#{URI.escape(href)}"
  download_file = File.join(OPTIONS[:DownloadDir], filename)
  if OPTIONS[:Force] || !File.exists?(download_file)
    log "downloading #{File.basename(href)}..."
    begin
      File.open(download_file, 'w') { |f| f.write(open(url).read)}
      log "\tsaved as #{download_file}"
    rescue Object => e
      FileUtils.rm(download_file)
      $stderr.puts "ERROR downloading #{url}: #{e.message}"
    end
  else
    log "skipping #{File.basename(href)}... already downloaded as #{download_file}"
  end
end

FileUtils.mkdir_p(OPTIONS[:DownloadDir])
h = Hpricot(open("#{BASE_URL}/pub/w/51/presentations.html"))
h.search('div.presentation').each do |presentation_node|
  href = presentation_node.at('a[@href^="/presentations/rails2007/"]')[:href]
  if OPTIONS[:DescriptiveFilenames]
    name = presentation_node.at('b a').inner_text.strip
    text = presentation_node.inner_text
    speaker = text[/Speaker\(s\):\s+(.*)\s*$/, 1]
    date = Date.parse(text[/Presentation Date:\s+(.*)\s*$/, 1])
    filename = [speaker, date, name, File.basename(href)].compact.map { |s| s.to_s.strip.gsub(/[^\w\.]/, '_').squeeze('_') }.join('-')
  else
    File.basename(href)
  end
  download(href, filename)
end

#!/usr/bin/env ruby

require 'rubygems'
require 'hpricot'
require 'open-uri'

base = 'http://www.web2expo.com'
h = Hpricot(open("#{base}/pub/w/51/presentations.html"))

h.search('div .presentation > a[@href^="/presentations/rails2007/"]').each do |a|
  url = "#{base}#{a[:href]}"
  if File.exists?(File.basename(url))
    puts "skipping #{url}... already downloaded"
  else
    puts "downloading #{url}..."
    `wget --quiet #{url}`
  end
end

class MarcelMolina
  include Heroes
  
  def <=>(other_hero)
    other_hero.name == 'Sylar' ? 0 : 1
  end
end