Results for: "partition"

Converts a pathname to an absolute pathname. Relative paths are referenced from the current working directory of the process unless dir_string is given, in which case it will be used as the starting point. If the given pathname starts with a “~” it is NOT expanded, it is treated as a normal directory name.

File.absolute_path("~oracle/bin")       #=> "<relative_path>/~oracle/bin"

Returns the pathname used to create file as a string. Does not normalize the name.

File.new("testfile").path               #=> "testfile"
File.new("/tmp/../tmp/xxx", "w").path   #=> "/tmp/../tmp/xxx"

Returns true if the named file is writable by the real user and group id of this process. See access(3)

If file_name is writable by others, returns an integer representing the file permission bits of file_name. Returns nil otherwise. The meaning of the bits is platform dependent; on Unix systems, see stat(2).

file_name can be an IO object.

File.world_writable?("/tmp")                  #=> 511
m = File.world_writable?("/tmp")
sprintf("%o", m)                              #=> "777"

Returns the locale charmap name. It returns nil if no appropriate information.

Debian GNU/Linux
  LANG=C
    Encoding.locale_charmap  #=> "ANSI_X3.4-1968"
  LANG=ja_JP.EUC-JP
    Encoding.locale_charmap  #=> "EUC-JP"

SunOS 5
  LANG=C
    Encoding.locale_charmap  #=> "646"
  LANG=ja
    Encoding.locale_charmap  #=> "eucJP"

The result is highly platform dependent. So Encoding.find(Encoding.locale_charmap) may cause an error. If you need some encoding object even for unknown locale, Encoding.find(“locale”) can be used.

Iterates the given block for each element with an index, which starts from offset. If no block is given, returns a new Enumerator that includes the index, starting from offset

offset

the starting index to use

Iterates the given block for each element with an arbitrary object, obj, and returns obj

If no block is given, returns a new Enumerator.

Example

to_three = Enumerator.new do |y|
  3.times do |x|
    y << x
  end
end

to_three_with_string = to_three.with_object("foo")
to_three_with_string.each do |x,string|
  puts "#{string}: #{x}"
end

# => foo:0
# => foo:1
# => foo:2

Returns the singleton class of obj. This method creates a new singleton class if obj does not have one.

If obj is nil, true, or false, it returns NilClass, TrueClass, or FalseClass, respectively. If obj is a Fixnum or a Symbol, it raises a TypeError.

Object.new.singleton_class  #=> #<Class:#<Object:0xb7ce1e24>>
String.singleton_class      #=> #<Class:String>
nil.singleton_class         #=> NilClass

Returns an array of the names of singleton methods for obj. If the optional all parameter is true, the list will include methods in modules included in obj. Only public and protected singleton methods are returned.

module Other
  def three() end
end

class Single
  def Single.four() end
end

a = Single.new

def a.one()
end

class << a
  include Other
  def two()
  end
end

Single.singleton_methods    #=> [:four]
a.singleton_methods(false)  #=> [:two, :one]
a.singleton_methods         #=> [:two, :one, :three]

Returns an array of instance variable names for the receiver. Note that simply defining an accessor does not create the corresponding instance variable.

class Fred
  attr_accessor :a1
  def initialize
    @iv = 3
  end
end
Fred.new.instance_variables   #=> [:@iv]

Similar to method, searches singleton method only.

class Demo
  def initialize(n)
    @iv = n
  end
  def hello()
    "Hello, @iv = #{@iv}"
  end
end

k = Demo.new(99)
def k.hi
  "Hi, @iv = #{@iv}"
end
m = k.singleton_method(:hi)
m.call   #=> "Hi, @iv = 99"
m = k.singleton_method(:hello) #=> NameError

Returns true if obj responds to the given method. Private and protected methods are included in the search only if the optional second parameter evaluates to true.

If the method is not implemented, as Process.fork on Windows, File.lchmod on GNU/Linux, etc., false is returned.

If the method is not defined, respond_to_missing? method is called and the result is returned.

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

Deserializes JSON string by constructing new Exception object with message m and backtrace b serialized with to_json

Returns a hash, that will be turned into a JSON object and represent this object.

Stores class name (Exception) with message m and backtrace array b as JSON string

Return a list of the local variable names defined where this NameError exception was raised.

Internal use only.

Creates an accessor method to allow assignment to the attribute symbol.id2name. String arguments are converted to symbols.

Checks for a constant with the given name in mod. If inherit is set, the lookup will also search the ancestors (and Object if mod is a Module).

The value of the constant is returned if a definition is found, otherwise a NameError is raised.

Math.const_get(:PI)   #=> 3.14159265358979

This method will recursively look up constant names if a namespaced class name is provided. For example:

module Foo; class Bar; end end
Object.const_get 'Foo::Bar'

The inherit flag is respected on each lookup. For example:

module Foo
  class Bar
    VAL = 10
  end

  class Baz < Bar; end
end

Object.const_get 'Foo::Baz::VAL'         # => 10
Object.const_get 'Foo::Baz::VAL', false  # => NameError

If the argument is not a valid constant name a NameError will be raised with a warning “wrong constant name”.

Object.const_get 'foobar' #=> NameError: wrong constant name foobar

Sets the named constant to the given object, returning that object. Creates a new constant if no constant with the given name previously existed.

Math.const_set("HIGH_SCHOOL_PI", 22.0/7.0)   #=> 3.14285714285714
Math::HIGH_SCHOOL_PI - Math::PI              #=> 0.00126448926734968

If sym or str is not a valid constant name a NameError will be raised with a warning “wrong constant name”.

Object.const_set('foobar', 42) #=> NameError: wrong constant name foobar

Says whether mod or its ancestors have a constant with the given name:

Float.const_defined?(:EPSILON)      #=> true, found in Float itself
Float.const_defined?("String")      #=> true, found in Object (ancestor)
BasicObject.const_defined?(:Hash)   #=> false

If mod is a Module, additionally Object and its ancestors are checked:

Math.const_defined?(:String)   #=> true, found in Object

In each of the checked classes or modules, if the constant is not present but there is an autoload for it, true is returned directly without autoloading:

module Admin
  autoload :User, 'admin/user'
end
Admin.const_defined?(:User)   #=> true

If the constant is not found the callback const_missing is not called and the method returns false.

If inherit is false, the lookup only checks the constants in the receiver:

IO.const_defined?(:SYNC)          #=> true, found in File::Constants (ancestor)
IO.const_defined?(:SYNC, false)   #=> false, not found in IO itself

In this case, the same logic for autoloading applies.

If the argument is not a valid constant name a NameError is raised with the message “wrong constant name name”:

Hash.const_defined? 'foobar'   #=> NameError: wrong constant name foobar

Removes the definition of the given constant, returning that constant’s previous value. If that constant referred to a module, this will not change that module’s name and can lead to confusion.

Invoked when a reference is made to an undefined constant in mod. It is passed a symbol for the undefined constant, and returns a value to be used for that constant. The following code is an example of the same:

def Foo.const_missing(name)
  name # return the constant name as Symbol
end

Foo::UNDEFINED_CONST    #=> :UNDEFINED_CONST: symbol returned

In the next example when a reference is made to an undefined constant, it attempts to load a file whose name is the lowercase version of the constant (thus class Fred is assumed to be in file fred.rb). If found, it returns the loaded class. It therefore implements an autoload feature similar to Kernel#autoload and Module#autoload.

def Object.const_missing(name)
  @looked_for ||= {}
  str_name = name.to_s
  raise "Class not found: #{name}" if @looked_for[str_name]
  @looked_for[str_name] = 1
  file = str_name.downcase
  require file
  klass = const_get(name)
  return klass if klass
  raise "Class not found: #{name}"
end

Returns an array of the names of class variables in mod. This includes the names of class variables in any included modules, unless the inherit parameter is set to false.

class One
  @@var1 = 1
end
class Two < One
  @@var2 = 2
end
One.class_variables          #=> [:@@var1]
Two.class_variables          #=> [:@@var2, :@@var1]
Two.class_variables(false)   #=> [:@@var2]

Makes a list of existing constants public.

Makes a list of existing constants private.