Results for: "String#[]"

Module::used_refinements

Returns an array of all modules used in the current scope. The ordering of modules in the resulting array is not defined.

module A
  refine Object do
  end
end

module B
  refine Object do
  end
end

using A
using B
p Module.used_refinements

produces:

[#<refinement:Object@B>, #<refinement:Object@A>]

Module#const_added

Invoked as a callback whenever a constant is assigned on the receiver

module Chatty
  def self.const_added(const_name)
    super
    puts "Added #{const_name.inspect}"
  end
  FOO = 1
end

produces:

Added :FOO

Module#method_undefined

Invoked as a callback whenever an instance method is undefined from the receiver.

module Chatty
  def self.method_undefined(method_name)
    puts "Undefining #{method_name.inspect}"
  end
  def self.some_class_method() end
  def some_instance_method() end
  class << self
    undef_method :some_class_method
  end
  undef_method :some_instance_method
end

produces:

Undefining :some_instance_method

Module#included_modules

Returns the list of modules included or prepended in mod or one of mod’s ancestors.

module Sub
end

module Mixin
  prepend Sub
end

module Outer
  include Mixin
end

Mixin.included_modules   #=> [Sub]
Outer.included_modules   #=> [Sub, Mixin]

Creates instance variables and corresponding methods that return the value of each instance variable. Equivalent to calling “attr:name” on each name in turn. String arguments are converted to symbols. Returns an array of defined method names as symbols.

Module#attr_accessor

Defines a named attribute for this module, where the name is symbol.id2name, creating an instance variable (@name) and a corresponding access method to read it. Also creates a method called name= to set the attribute. String arguments are converted to symbols. Returns an array of defined method names as symbols.

module Mod
  attr_accessor(:one, :two) #=> [:one, :one=, :two, :two=]
end
Mod.instance_methods.sort   #=> [:one, :one=, :two, :two=]

Module#const_get

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

Module#const_set

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

Module#remove_const

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.

Module#class_variables

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]

Module#public_constant

Makes a list of existing constants public.

Module#deprecate_constant

Makes a list of existing constants deprecated. Attempt to refer to them will produce a warning.

module HTTP
  NotFound = Exception.new
  NOT_FOUND = NotFound # previous version of the library used this name

  deprecate_constant :NOT_FOUND
end

HTTP::NOT_FOUND
# warning: constant HTTP::NOT_FOUND is deprecated

Module#define_method

Defines an instance 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. If a block or the method parameter has parameters, they’re used as method parameters. This block is evaluated using instance_eval.

class A
  def fred
    puts "In Fred"
  end
  def create_method(name, &block)
    self.class.define_method(name, &block)
  end
  define_method(:wilma) { puts "Charge it!" }
  define_method(:flint) {|name| puts "I'm #{name}!"}
end
class B < A
  define_method(:barney, instance_method(:fred))
end
a = B.new
a.barney
a.wilma
a.flint('Dino')
a.create_method(:betty) { p self }
a.betty

produces:

In Fred
Charge it!
I'm Dino!
#<B:0x401b39e8>

Module#method_defined?

Returns true if the named method is defined by mod. If inherit is set, the lookup will also search mod’s ancestors. Public and protected methods are matched. String arguments are converted to symbols.

module A
  def method1()  end
  def protected_method1()  end
  protected :protected_method1
end
class B
  def method2()  end
  def private_method2()  end
  private :private_method2
end
class C < B
  include A
  def method3()  end
end

A.method_defined? :method1              #=> true
C.method_defined? "method1"             #=> true
C.method_defined? "method2"             #=> true
C.method_defined? "method2", true       #=> true
C.method_defined? "method2", false      #=> false
C.method_defined? "method3"             #=> true
C.method_defined? "protected_method1"   #=> true
C.method_defined? "method4"             #=> false
C.method_defined? "private_method2"     #=> false

BigDecimal::interpret_loosely

No documentation available

BigDecimal#to_int

Returns the value as an Integer.

If the BigDecimal is infinity or NaN, raises FloatDomainError.

Date::valid_ordinal?

Returns true if the arguments define a valid ordinal date, false otherwise:

Date.valid_ordinal?(2001, 34)  # => true
Date.valid_ordinal?(2001, 366) # => false

See argument start.

Related: Date.jd, Date.ordinal.

Date::gregorian_leap?

Returns true if the given year is a leap year in the proleptic Gregorian calendar, false otherwise:

Date.gregorian_leap?(2000) # => true
Date.gregorian_leap?(2001) # => false

Related: Date.julian_leap?.

Date#new_start

Returns a copy of self with the given start value:

d0 = Date.new(2000, 2, 3)
d0.julian? # => false
d1 = d0.new_start(Date::JULIAN)
d1.julian? # => true

See argument start.

IO#cursor_right

No documentation available

IO#erase_line

No documentation available

IO#wait_writable

Waits until IO is writable and returns a truthy value or a falsy value when times out.

You must require ‘io/wait’ to use this method.

IO::try_convert

Attempts to convert object into an IO object via method to_io; returns the new IO object if successful, or nil otherwise:

IO.try_convert(STDOUT)   # => #<IO:<STDOUT>>
IO.try_convert(ARGF)     # => #<IO:<STDIN>>
IO.try_convert('STDOUT') # => nil

IO#each_line

Calls the block with each remaining line read from the stream; returns self. Does nothing if already at end-of-stream; See Line IO.

With no arguments given, reads lines as determined by line separator $/:

f = File.new('t.txt')
f.each_line {|line| p line }
f.each_line {|line| fail 'Cannot happen' }
f.close

Output:

"First line\n"
"Second line\n"
"\n"
"Fourth line\n"
"Fifth line\n"

With only string argument sep given, reads lines as determined by line separator sep; see Line Separator:

f = File.new('t.txt')
f.each_line('li') {|line| p line }
f.close

Output:

"First li"
"ne\nSecond li"
"ne\n\nFourth li"
"ne\nFifth li"
"ne\n"

The two special values for sep are honored:

f = File.new('t.txt')
# Get all into one string.
f.each_line(nil) {|line| p line }
f.close

Output:

"First line\nSecond line\n\nFourth line\nFifth line\n"

f.rewind
# Get paragraphs (up to two line separators).
f.each_line('') {|line| p line }

Output:

"First line\nSecond line\n\n"
"Fourth line\nFifth line\n"

With only integer argument limit given, limits the number of bytes in each line; see Line Limit:

f = File.new('t.txt')
f.each_line(8) {|line| p line }
f.close

Output:

"First li"
"ne\n"
"Second l"
"ine\n"
"\n"
"Fourth l"
"ine\n"
"Fifth li"
"ne\n"

With arguments sep and limit given, combines the two behaviors:

Calls with the next line as determined by line separator sep.
But returns no more bytes than are allowed by the limit.

Optional keyword argument chomp specifies whether line separators are to be omitted:

f = File.new('t.txt')
f.each_line(chomp: true) {|line| p line }
f.close

Output:

"First line"
"Second line"
""
"Fourth line"
"Fifth line"

Returns an Enumerator if no block is given.

IO#each_codepoint

Calls the given block with each codepoint in the stream; returns self:

f = File.new('t.rus')
a = []
f.each_codepoint {|c| a << c }
a # => [1090, 1077, 1089, 1090]
f.close

Returns an Enumerator if no block is given.