Ruby - the most interesting language in the world

3VCZ +FTTF8PMHBNPUU!KXP )PVTUPO0QFO%FW .BSDI Friday, March 8, 13

UIFNPTUJOUFSFTUJOHMBOHVBHFJOUIFXPSME Friday, March 8, 13

1SFBNCMF UIFPWFSWJFX Friday, March 8, 13

3VCZ%JWJEFEJOUPUISFFTFDUJPOT 0CKFDU0SJFOUFE 4ZTUFN)BDLJOH 1FSM4DSJQUJOH Friday, March 8, 13

)JTUPSZ $SFBUFECZ:VLJIJSP.BUTVNPUPJO NBU[ )FZ UIBUTZFBSTBHP ZBZ Friday, March 8,
13

.BU[!-43$ Friday, March 8, 13

CUX #ZUIF8BZ NBU[JTOJDF .*/*48"/ .BU[JT/JDF 4P8F"SF/JDF Friday, March 8, 13

)JTUPSZ$POUJOVFE 8BTEJTDPWFSFEJOFBSMZTCZ%BWF 5IPNBT $BVHIUPOXJUIFBSMZBEPQUFSTUSZJOHUP NPWFBXBZGSPN1FSM $BVHIUpSFXJUI%BWJE)FJOFNFJIFS )BOTPOT3BJMTJO Friday, March 8,
13

1MBOPG"UUBDL 8FXJMMPOMZDPWFS00QBSUPGSVCZ TJODFJUTUIFPOMZQBSUBOZPOFVTFT 4ZOUBYBOE5IFPSZ #SFBL -JWF$PEJOH Friday, March 8,
13

4ZOUBY Friday, March 8, 13

$MBTTFT class Page end class Author end Friday, March 8,
13

.FUIPET def name “hello world” end >> name => “hello
world” Friday, March 8, 13

$POTUBOUT class MyClass MAXIMUM = 5 def max MAXIMUM end
end MyClass::MAXIMUM => 5 MyClass.new.max => 5 Friday, March 8, 13

$BTF4XJUDI def do_things(object) case object.status when :active # something when
:almost_active # something when :inactive # something else # something else end end Friday, March 8, 13

&YDFQUJPOT File.read('/usr/var/non_existent') Errno::ENOENT: No such file or directory - /usr/
var/non_existent ! from (irb):41:in `read' def read File.read('/usr/var/non_existent') rescue Errno::ENOENT puts 'hey, file not found' end >> read hey, file not found => nil Friday, March 8, 13

.FUIPE1BSBNFUFST "SHVNFOUT def say_things(words) puts words end >> say_thing “yo!”
yo => nil Friday, March 8, 13

7BSJBCMFT class Person def say_hi name = "Peter" "hi #{name}"
end end >> Person.new.say_hi Friday, March 8, 13

7BSJBCMFT class Person def say_hi name = "Peter" "hi #{name}"
end end >> Person.new.say_hi => "hi Peter" Friday, March 8, 13

7BSJBCMFT BSFMPDBMTDPQFE class Person def say_hi name = "Peter" end
def whats_my_name name end end Friday, March 8, 13

7BSJBCMFT BSFMPDBMTDPQFE >> person = Person.new => #<Person:0x007feb9613b8c8> >> person.say_hi
=> "Peter" >> person.whats_my_name NameError: undefined local variable or method `name' for #<Person:0x007feb9613b8c8> ! from (irb):27:in `whats_my_name' ! ... Friday, March 8, 13

*OTUBODF7BSJBCMF class Person def say_hi @name = "Peter" end def
whats_my_name @name end end Friday, March 8, 13

*OTUBODF7BSJBCMFTBSFDMBTT TDPQFE >> person = Person.new => #<Person:0x007feb9613b8c8> >> person.say_hi
=> "Peter" >> person.whats_my_name => “Peter” Friday, March 8, 13

1VCMJD"DDFTTJCJMJUZ class Person def initialize @name = "Peter" end end
Friday, March 8, 13

1VCMJD"DDFTTJCJMJUZ >> person = Person.new => #<Person:0x007feb962e6a10> >> person.name NoMethodError:
undefined method `name' for #<Person: 0x007feb962e6a10> ! from (irb):52 Friday, March 8, 13

BUUS@SFBEFS class Person attr_reader :name def initialize @name = "Peter"
end end Friday, March 8, 13

1VCMJD"DDFTTJCJMJUZ >> person = Person.new => #<Person:0x007feb962e6a10> >> person.name =>
“Peter” Friday, March 8, 13

BUUS@BDDFTTPS class Person attr_accessor :name end >> person = Person.new
=> #<Person:0x007feb96346dc0> >> person.name = "Pedro" => "Pedro" Friday, March 8, 13

.PEVMFT module Nice def when_person_says_hello "hi! how are you?" end
end class Person include Nice end Friday, March 8, 13

.PEVMFT >> Person.new.when_person_says_hello => “hi how are you?” Friday, March
8, 13

*OIFSJUBODF class Person attr_reader :name def initialize @name = "Peter"
end end class Pedro < Person end Friday, March 8, 13

*OIFSJUBODF >> pedro = Pedro.new => #<Pedro:0x007feb96db9780 @name="Peter"> >> pedro.name
=> "Peter" >> pedro.is_a? Person => true Friday, March 8, 13

&OVNFSBCMFT Friday, March 8, 13

DPMMFDUJPOTPS BSSBZT Friday, March 8, 13

-PPQJOH 3.times do puts "hi" end hi hi hi =>
3 Friday, March 8, 13

-PPQJOH [1, 2, 3].each do |i| puts i * 25
end 25 50 75 => [1, 2, 3] Friday, March 8, 13

.BQ [1, 2, 3].map do |i| i * 25 end
[1, 2, 3].map{ |i| i * 25 } => [25, 50, 75] Friday, March 8, 13

*OKFDU [5, 10, 15].inject do |memo, i| memo + i
end [5, 10, 15].inject(:+) => 30 Friday, March 8, 13

*OKFDU8PX&YBNQMF %w{ cat sheep bear }.inject do |memo, word| memo.length
> word.length ? memo : word end => "sheep" Friday, March 8, 13

1VUJU"MM5PHFUIFS Account.all.reject{|i| i.active?}.map{|a| a.amount_due}.inject(:+) Account .all .reject{|a| a.active?} .map{|a| a.amount_due}
.inject(:+) Friday, March 8, 13

[PNH Friday, March 8, 13

)BTIFT Friday, March 8, 13

)BTI.BQPS %JDUJPOBSZ Friday, March 8, 13

)BTI4ZOUBY our_hash = Hash.new our_hash["location"] = "Houston" our_hash["location"] => "Houston"
our_hash = {} our_hash["location"] = "Houston" our_hash.fetch("location") => "Houston" Friday, March 8, 13

)BTIXIFONJTTJOH our_hash = Hash.new our_hash["location"] = "Houston" our_hash["area"] => nil
our_hash = {} our_hash["location"] = "Houston" our_hash.fetch("area") KeyError: key not found: "area" ! from (irb):300:in `fetch' ! from (irb):300 Friday, March 8, 13

)BTI%FGBVMUT our_hash = Hash.new our_hash["location"] = "Houston" our_hash["area"] || "Texas"
=> “Texas” our_hash = {} our_hash["location"] = "Houston" our_hash.fetch("area", "Texas") => “Texas” Friday, March 8, 13

&YUSB"SHVNFOUTBSF )BTIFE def gimme_gimme(name, args) puts "location: #{args[:location]}" puts "location:
#{args[:area]}" end gimme_gimme "roy", location: "nyc", area: "NY" location: nyc location: NY Friday, March 8, 13

UZQFTPG4USJOHT lSFHVMBSTUSJOH\bIJ`^z lSFHVMBSTUSJOHIJz bOPOJOUFSQSFUFETUSJOH\OBNF^` bOPOJOUFSQSFUFETUSJOH\OBNF^` TZNCPM Friday, March 8, 13

#MPDLTBOE 1SPDT Friday, March 8, 13

5JNJOH&YBNQMF def how_long? start_time = Time.now result = yield end_time
= Time.now [result, end_time - start_time] end how_long? do sleep(2) "pretend call to an api" end Friday, March 8, 13

5JNJOH&YBNQMF => ["pretend call to an api", 2.00012] Friday, March
8, 13

-PHHJOH&YBNQMF class EasyLogger def initialize @log = [] end def
log(description) @log << "#{description} - #{Time.now}" yield end def entries @log end end logger = EasyLogger.new %w(sarah bobby jungle stuff).map do |word| logger.log "reverse #{word}" do word.reverse end end Friday, March 8, 13

-PHHJOH&YBNQMF => ["haras", "ybbob", "elgnuj", "ffuts"] >> logger.entries ["reverse sarah
- 2013-03-07 11:47:25 -0600", "reverse bobby - 2013-03-07 11:47:25 -0600", "reverse jungle - 2013-03-07 11:47:25 -0600", "reverse stuff - 2013-03-07 11:47:25 -0600"] http://rubyﬁddle.com/riddles/10504/9 Friday, March 8, 13

&WFSZ.FUIPEBTB#MPDL PQUJPOBMMZ def name(v1, *other_args, &the_block) Friday, March 8, 13

#MPDLJTJHOPSFEJGOPU ZJFMEFEUP def x_plus_y(x, y) x+y end x_plus_y( "a", "b")
do puts "I was called!" end => "ab" Friday, March 8, 13

#MPDLJTJHOPSFEJGOPU ZJFMEFEUP def x_plus_y(x, y) yield x+y end x_plus_y( "a",
"b") do puts "I was called!" end I was called! => "ab" Friday, March 8, 13

B1SPDJTBDBMMBCMFPCKFDU my_callback = Proc.new { puts Time.now } def show_off(callable)
puts Time.now sleep(2) callable.call end show_off my_callback Friday, March 8, 13

B1SPDJTBDBMMBCMFPCKFDU my_callback = Proc.new { puts Time.now } def show_off(callable)
puts Time.now sleep(2) callable.call end show_off my_callback 2013-03-07 15:56:48 -0600 2013-03-07 15:56:50 -0600 Friday, March 8, 13

(PPEVTF$BMMCBDLT yay = Proc.new {|report| DPS.submit! report } boo =
Proc.new {|report| FailureLog.log report } methods = {success: yay, failure: boo} class Processor def process(report, callbacks={}) if report.valid? callbacks.fetch(:success, Proc.new).call(report) else callbacks.fetch(:failure, Proc.new).call(report) end end end Processor.process(report, methods) Friday, March 8, 13

BQQSPWF Friday, March 8, 13

.FUB 1SPHSBNNJOH Friday, March 8, 13

0QFOJOH"OZ$MBTT &WFS class Fixnum def is_answer_to_everything? self == 42 end
end 5.is_answer_to_everything? Friday, March 8, 13

0QFOJOH"OZ$MBTT &WFS class Fixnum def is_answer_to_everything? self == 42 end
end 5.is_answer_to_everything? => false Friday, March 8, 13

#VUXIBUJTUIFBOTXFS (1..100) .find(&:is_answer_to_everything?) => 42 Friday, March 8, 13

#VUXIBUJTUIFBOTXFS class Fixnum def is_answer_to_everything? self == 42 end end
(1..Float::INFINITY).find(&:is_answer _to_everything?) => 42 # Note it did not error! Friday, March 8, 13

#FJOH&WJM class Fixnum def ==(other) true end end 5 ==
5 => true Friday, March 8, 13

#FJOH&WJM class Fixnum def ==(other) true end end 5 ==
5 => true 6 == 62 => true Friday, March 8, 13

*OTUBODF&WBM 42.instance_eval do def is_answer_to_everything? self == 42 end end
4.is_answer_to_everything? NoMethodError: undefined method `is_answer_to_everything?' for 4:Fixnum 42.is_answer_to_everything? => true Friday, March 8, 13

&YUFOE0CKFDUTXJUI.PEVMFT user = Object.new admin = Object.new module Purchaseable def
purchase! # Order.create! end end admin.extend Purchaseable user.purchase! admin.purchase! Friday, March 8, 13

&YUFOE0CKFDUTXJUI.PEVMFT user.purchase! NoMethodError: undefined method `purchase!' admin.purchase! => nil #
it works! Friday, March 8, 13

.FUIPE.JTTJOH class OhHai def method_missing(name, *args, &block) if name.to_s =~
/^say_/ name.to_s.gsub('say_', '').upcase else super end end end Friday, March 8, 13

/^say_/ name.to_s.gsub('say_', '').upcase else super end end end OhHai.new.say_hello Friday, March 8, 13

/^say_/ name.to_s.gsub('say_', '').upcase else super end end end => "HELLO" OhHai.new.say_hello Friday, March 8, 13

/^say_/ name.to_s.gsub('say_', '').upcase else super end end end => "HELLO" OhHai.new.say_wasssup OhHai.new.say_hello Friday, March 8, 13

/^say_/ name.to_s.gsub('say_', '').upcase else super end end end => "HELLO" OhHai.new.say_wasssup OhHai.new.say_hello => "WASSSUP" Friday, March 8, 13

*OEFFE Friday, March 8, 13

"DUJWF4VQQPSU $PPM4UVGG Friday, March 8, 13

6UJMJUZDMBTTFTBOE 3VCZFYUFOTJPOT GSPN3BJMT Friday, March 8, 13

$PPM4UVGG require 'active_support/all' 1.day.from_now => 2013-03-08 13:07:28 -0600 3.weeks.ago =>
2013-02-14 13:08:27 -0600 (1..50).to_a.forty_two => 42 Friday, March 8, 13

<NPSF>$PPM4UVGG require 'active_support/all' "2012-03-31".to_date => Sat, 31 Mar 2012 {first:
"Jesse", last: "Wolgamott"}.to_json => {"first":"Jesse","last":"Wolgamott"} # and much much more Friday, March 8, 13

5FTUJOH Friday, March 8, 13

8IBUXFXBOUUPUFTU class CloneWar def war? false end end Friday, March
8, 13

.JOJ5FTU require 'minitest/autorun' class TestCloneWar < MiniTest::Unit::TestCase def test_should_not_be_at_war assert_equal
false, CloneWar.new.war? end end Friday, March 8, 13

34QFD require 'rspec' describe CloneWar do it "should not be
at war" do subject.war? should be_false end end Friday, March 8, 13

FJUIFSJTHSFBU Friday, March 8, 13

&DPTZUFN Friday, March 8, 13

5IF3VCZ&DPTZTUFN 3BJMTUIFCJHEBEEZ (FNTSFVTBCMFMJCSBSJFT #VOEMFSJOTUBMMTHFNTEFQFOEFODJFT Friday, March 8, 13

4UBDL Friday, March 8, 13

(FOFSBMMZ1SFGFSSFE4UBDL 1PTUHSF42-GPSEC NFNDBDIFEBOESFEJTUPIFMQ OHJOYGPSXFCTFSWFS VOJDPSOPSQVNBGPSSBJMTTFSWFS IFSPLVGPSIPTUJOH HJUGPSEFQMPZ PS DBQJTUSBOPUPEFQMPZ Friday,
March 8, 13

<pO> *`N+FTTF8PMHBNPUU *DSFBUFBOEUSBJOBU$PNBM1SPEVDUJPOT *SVO3VCZ0GG3BJMT Friday, March 8, 13

Ruby - the most interesting language in the world

Ruby - the most interesting language in the world

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