Results for: "partition"

Returns true if the given instance variable is defined in obj. String arguments are converted to symbols.

class Fred
  def initialize(p1, p2)
    @a, @b = p1, p2
  end
end
fred = Fred.new('cat', 99)
fred.instance_variable_defined?(:@a)    #=> true
fred.instance_variable_defined?("@b")   #=> true
fred.instance_variable_defined?("@c")   #=> false

Removes the named instance variable from obj, returning that variable’s value.

class Dummy
  attr_reader :var
  def initialize
    @var = 99
  end
  def remove
    remove_instance_variable(:@var)
  end
end
d = Dummy.new
d.var      #=> 99
d.remove   #=> 99
d.var      #=> nil

Defines a singleton method in the receiver. The method parameter can be a Proc, a Method or an UnboundMethod object. If a block is specified, it is used as the method body.

class A
  class << self
    def class_name
      to_s
    end
  end
end
A.define_singleton_method(:who_am_i) do
  "I am: #{class_name}"
end
A.who_am_i   # ==> "I am: A"

guy = "Bob"
guy.define_singleton_method(:hello) { "#{self}: Hello there!" }
guy.hello    #=>  "Bob: Hello there!"

DO NOT USE THIS DIRECTLY.

Hook method to return whether the obj can respond to id method or not.

When the method name parameter is given as a string, the string is converted to a symbol.

See respond_to?, and the example of BasicObject.

Removes the definition of the sym, returning that constant’s value.

class Dummy
  @@var = 99
  puts @@var
  remove_class_variable(:@@var)
  p(defined? @@var)
end

produces:

99
nil

Returns the value of the given class variable (or throws a NameError exception). The @@ part of the variable name should be included for regular class variables. String arguments are converted to symbols.

class Fred
  @@foo = 99
end
Fred.class_variable_get(:@@foo)     #=> 99

Sets the class variable named by symbol to the given object. If the class variable name is passed as a string, that string is converted to a symbol.

class Fred
  @@foo = 99
  def foo
    @@foo
  end
end
Fred.class_variable_set(:@@foo, 101)     #=> 101
Fred.new.foo                             #=> 101

Returns true if the given class variable is defined in obj. String arguments are converted to symbols.

class Fred
  @@foo = 99
end
Fred.class_variable_defined?(:@@foo)    #=> true
Fred.class_variable_defined?(:@@bar)    #=> false

Returns true if ios will be closed on exec.

f = open("/dev/null")
f.close_on_exec?                 #=> false
f.close_on_exec = true
f.close_on_exec?                 #=> true
f.close_on_exec = false
f.close_on_exec?                 #=> false

Sets a close-on-exec flag.

f = open("/dev/null")
f.close_on_exec = true
system("cat", "/proc/self/fd/#{f.fileno}") # cat: /proc/self/fd/3: No such file or directory
f.closed?                #=> false

Ruby sets close-on-exec flags of all file descriptors by default since Ruby 2.0.0. So you don’t need to set by yourself. Also, unsetting a close-on-exec flag can cause file descriptor leak if another thread use fork() and exec() (via system() method for example). If you really needs file descriptor inheritance to child process, use spawn()‘s argument such as fd=>fd.

Packs port and host as an AF_INET/AF_INET6 sockaddr string.

Socket.sockaddr_in(80, "127.0.0.1")
#=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00"

Socket.sockaddr_in(80, "::1")
#=> "\n\x00\x00P\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00"

Unpacks sockaddr into port and ip_address.

sockaddr should be a string or an addrinfo for AF_INET/AF_INET6.

sockaddr = Socket.sockaddr_in(80, "127.0.0.1")
p sockaddr #=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00"
p Socket.unpack_sockaddr_in(sockaddr) #=> [80, "127.0.0.1"]

Packs path as an AF_UNIX sockaddr string.

Socket.sockaddr_un("/tmp/sock") #=> "\x01\x00/tmp/sock\x00\x00..."

Unpacks sockaddr into path.

sockaddr should be a string or an addrinfo for AF_UNIX.

sockaddr = Socket.sockaddr_un("/tmp/sock")
p Socket.unpack_sockaddr_un(sockaddr) #=> "/tmp/sock"

Returns true for IPv6 multicast site-local scope address. It returns false otherwise.

Returns true when OLE object has OLE method, otherwise returns false.

ie = WIN32OLE.new('InternetExplorer.Application')
ie.ole_respond_to?("gohome") => true

Invoked as a callback whenever a singleton method is added to the receiver.

module Chatty
  def Chatty.singleton_method_added(id)
    puts "Adding #{id.id2name}"
  end
  def self.one()     end
  def two()          end
  def Chatty.three() end
end

produces:

Adding singleton_method_added
Adding one
Adding three

Invoked as a callback whenever a singleton method is removed from the receiver.

module Chatty
  def Chatty.singleton_method_removed(id)
    puts "Removing #{id.id2name}"
  end
  def self.one()     end
  def two()          end
  def Chatty.three() end
  class << self
    remove_method :three
    remove_method :one
  end
end

produces:

Removing three
Removing one

Invoked as a callback whenever a singleton method is undefined in the receiver.

module Chatty
  def Chatty.singleton_method_undefined(id)
    puts "Undefining #{id.id2name}"
  end
  def Chatty.one()   end
  class << self
     undef_method(:one)
  end
end

produces:

Undefining one

Checks for a method provided by this the delegate object by forwarding the call through _getobj_.

Same as each, but the row index and column index in addition to the element

Matrix[ [1,2], [3,4] ].each_with_index do |e, row, col|
  puts "#{e} at #{row}, #{col}"
end
  # => Prints:
  #    1 at 0, 0
  #    2 at 0, 1
  #    3 at 1, 0
  #    4 at 1, 1

Returns the directories in the current shell’s PATH environment variable as an array of directory names. This sets the system_path for all instances of Shell.

Example: If in your current shell, you did:

$ echo $PATH
/usr/bin:/bin:/usr/local/bin

Running this method in the above shell would then return:

["/usr/bin", "/bin", "/usr/local/bin"]