Algunos métodos de ruby sobre diferentes objetos

arrays.rb

a = [ "a", "b", "c", "d" ]

a.collect {|x| x + "!"}                #=> ["a!", "b!", "c!", "d!"]

a.map.with_index {|x, i| x * i}        #=> ["", "b", "cc", "ddd"]

a                                      #=> ["a", "b", "c", "d"]

[ "a", nil, "b", nil, "c" ].compact!   #=> [ "a", "b", "c" ]

[ "a", "b", "c" ].compact!             #=> nil

[1,2,3,4,5].select {|num| num.even? }  #=> [2, 4]

integers.rb

1234.integer?                 #=> true
 
-12345.abs                    #=> 12345
 
36.lcm(60)                    #=> 180
 
(-1).next                     #=> 0

1.succ                        #=> 2

5.times {|i| print i, " " }   #=> 0 1 2 3 4

strings.rb

"Ho! " * 3                #=> "Ho! Ho! Ho! "

"Ho! " * 0                #=> ""

a = "hello "

a << "world"              #=> "hello world"

a << 33                   #=> "hello world!"

"hello".capitalize        #=> "Hello"

"HELLO".capitalize        #=> "Hello"

"123ABC".capitalize       #=> "123abc"

"hello".center(4)         #=> "hello"

"hello".center(20)        #=> "       hello        "

"hello".center(20, '123') #=> "1231231hello12312312"

"hEllO".downcase          #=> "hello"

"hEllO".upcase            #=> "HELLO"