my web space
module Kernel def random_uc(size=16) Array.new(size){ rand(26)+65 }.pack('C*') end def random_lc(size=16) Array.new(size){ rand(26)+97 }.pack('C*') end def random_num(size=16) Array.new(size){ rand(10) }.join end end random_uc => "HRTWYJBJEZDKYPTJ" random_lc => "onxkvkezqukspmcx" random_num => "5862195932579950"
mkdir -p RAILS_ROOT/vendor/plugins/core_methods
mkdir -p RAILS_ROOT/vendor/plugins/core_methods/init.rb
The content of init.rb:
module Rails empty_and_nil = %q{def empty_and_nil; self.empty?? nil : self end} Array.send :class_eval, empty_and_nil Hash.send :class_eval, empty_and_nil end
The namespace Rails isn’t necessary, it’s a cosmetic feature.
class Array def empty_and_nil self.empty?? nil : self end end result = [1,2,3].empty_and_nil # [1, 2, 3] result = [].empty_and_nil # nil
Use nil when the return is a boolean value.
Use false when the return is either false or not true object.
Otherwise they have pretty much the same semantic:
nil == false => false nil.nil? => true false.nil? => false true.nil? => false if !nil && !false puts 'true' end if nil.nil? && !true.nil? puts 'true' end >> TrueClass.ancestors => [TrueClass, Object, Kernel] >> FalseClass.ancestors => [FalseClass, Object, Kernel] >> NilClass.ancestors => [NilClass, Object, Kernel]
mt = Array.new(10) { |e| Hash.new { |h,k| h[k] = k * e } } mt[1][2] => 2 mt[2][2] => 4 mt[5][4] => 20 mt[9][5] => 45
Sample .bashrc file:
# decimal to binary alias d2b='ruby -e "puts ARGV.first.to_i.to_s(2)"' # decimal to hexademical alias d2h='ruby -e "puts ARGV.first.to_i.to_s(16)"' # decimal to octal alias d2o='ruby -e "puts ARGV.first.to_i.to_s(8)"' # binary to decimal alias b2d='ruby -e "puts eval(%q|0b| + ARGV.first)"' # binary to hexademical alias b2h='ruby -e "puts eval(%q|0b| + ARGV.first).to_s(16)"' # binary to octal alias b2o='ruby -e "puts eval(%q|0b| + ARGV.first).to_s(8)"' # hexademical to decimal alias h2d='ruby -e "puts eval(%q|0x| + ARGV.first)"' # hexademical to binary alias h2b='ruby -e "puts eval(%q|0x| + ARGV.first).to_s(2)"' # hexademical to octal alias h2o='ruby -e "puts eval(%q|0x| + ARGV.first).to_s(8)"' # octal to decimal alias o2d='ruby -e "puts eval(%q|0o| + ARGV.first)"' # octal to binary alias o2b='ruby -e "puts eval(%q|0o| + ARGV.first).to_s(2)"' # octal to hexademical alias o2h='ruby -e "puts eval(%q|0o| + ARGV.first).to_s(16)"'
require 'rubygems' require 'google_translate' tr = Google::Translate.new # from English to German tr.translate :from => "en", :to => "de", :text => "Hello, World!" => Hallo, Welt! # from English to Spanish tr.translate :from => "en", :to => "es", :text => "Hello, World!" => Hola, Mundo! # WWW::Mechanize constructor usage tr = Google::Translate.new { |agent| agent.user_agent_alias = 'Mac Safari' }
require 'benchmark' n = 1_000_000 s = " : : : " Benchmark.bm do |x| x.report("tr:") { n.times{ s.tr(":", ";") } } x.report("tr_s:") { n.times{ s.tr_s(":", ";") } } x.report("gsub:") { n.times{ s.gsub(":", ";") } } end
Right, tr beats the other methods:
user system total real
tr: 2.760000 0.120000 2.880000 ( 2.897022)
tr_s: 5.310000 0.240000 5.550000 ( 5.822026)
gsub: 8.850000 0.200000 9.050000 ( 9.311452)
In essence (from bulgarian to japanese):
agent = WWW::Mechanize.new agent.post("http://translate.google.com/translate_t", "sl" => "bg", "tl" => "ja", "text" => "Здравей, свят!").search("#result_box").inner_html
results in こんにちは、世界！
String methods:
"a".upto("z"){ |i| puts i }
a = String.new "a" 0.upto(0){ p a } 1.upto(25){ p a.next! }
Range method:
("a".."z").each{ |e| puts e }
9th sphere web design