I’ve needed to print simple table as
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1 2 3 5 7 2 4 6 10 14 3 6 9 15 21 5 10 15 25 35 7 14 21 35 49 |
as you can see, x = y, cell in table = x*y (x*x to be exact)
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primes = [2, 3, 5, 7] primes = [1] + primes # we need that to print x/y axis puts primes.map{|i| primes.map{|a| a*i}}.map{|i| ['%4i']*primes.length*' '%i} |
Tried simple Sieve of Eratosthenes in Ruby …
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class MyPrime attr_reader :primes # there we can read then # compute prime numbers up to limit, default is 20 def initialize(limit = 20) @primes = [] limit = limit.to_i return if limit.to_i < 2 arr = Hash[*((2..limit).to_a*2).sort] # we can use .zip too (2..Math.sqrt(limit)).each do |i| next unless arr[i] # already removed (i*i..limit).step(i).each{|k| arr.delete(k)} end @primes = arr.keys.sort # return just keys end end |
we can add some tests
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require 'test/unit' require 'my_prime' class TestMyPrime < Test::Unit::TestCase def test_20_primes primes = MyPrime.new(20) assert_equal [2, 3, 5, 7, 11, 13, 17, 19], primes.primes end def test_wo_param primes = MyPrime.new assert_equal [2, 3, 5, 7, 11, 13, 17, 19], primes.primes end def test_less_than_2 primes = MyPrime.new(1) assert_equal [], primes.primes end def test_limit_eq_2 primes = MyPrime.new(2) assert_equal [2], primes.primes end def test_limit_is_string primes = MyPrime.new('20') assert_equal [2, 3, 5, 7, 11, 13, 17, 19], primes.primes end def test_limit_is_float primes = MyPrime.new(20.50) assert_equal [2, 3, 5, 7, 11, 13, 17, 19], primes.primes end end |
Apple has released new version of iPhone OS4 SDK (SDK4) Beta 4…
Build: 10M2252
Download & Availability: iPhone Developer Program/Members only
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# parse caller to fetch filename, method &amp; line of call def parse_caller(at) if /^(.+?):(\d+)(?::in `(.*)')?/ =~ at file = Regexp.last_match[1] line = Regexp.last_match[2].to_i method = Regexp.last_match[3] [file, line, method] end end |
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file, line, method = parse_caller(caller(1).first) |
in helper
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def show_date(date) return '' if date.nil? || date==0 l(Time.at(date), :format => :ddate) end |
in config/locale/en.yml (for example)
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date: formats: ddate: %d.%m.%Y |
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module I18n::Backend class Simple protected def pluralize(locale, entry, count) return entry unless entry.is_a?(Hash) and count key = :zero if count == 0 && entry.has_key?(:zero) key ||= count == 1 ? :one : (2..4).include?(count) ? :few : :other raise InvalidPluralizationData.new(entry, count) unless entry.has_key?(key) entry[key] end end # class end # module |
place this in your application.rb (eg)
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class String def translit Unicode.normalize_KD(self).unpack('U*').select{ |cp| cp < 127 }.pack('U*').gsub(/ /,'-').downcase end end |
New version of rails comes with a great feature called named_scope.
# in your model.rb
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class Model < ActiveRecord::Base has_many ... belongs_to ... named_scope :active, :conditions => {:state => 'active'} named_scope :today, :conditions => ['date_created between ? and ?', Time.today.to_i, Time.today.to_i+3600*24-1] named_scope :by_date_asc, :order => 'date_created asc' named_scope :by_date_desc, :order => 'date_created desc' named_scope :user_name, lambda {|name| {:conditions => {:username => name}} |
and you can use its as:
# somewhere in your code
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@data = Model.today @data = Model.today.active.by_date_asc @data = Model.user_name('some user').active.today.by_date_desc |