Returns true if filepath points to a character device, false otherwise.
File.chardev?($stdin) # => true File.chardev?('t.txt') # => false
Returns a replicated encoding of enc whose name is name. The new encoding should have the same byte structure of enc. If name is used by another encoding, raise ArgumentError.
Checks the compatibility of two objects.
If the objects are both strings they are compatible when they are concatenatable. The encoding of the concatenated string will be returned if they are compatible, nil if they are not.
Encoding.compatible?("\xa1".force_encoding("iso-8859-1"), "b") #=> #<Encoding:ISO-8859-1> Encoding.compatible?( "\xa1".force_encoding("iso-8859-1"), "\xa1\xa1".force_encoding("euc-jp")) #=> nil
If the objects are non-strings their encodings are compatible when they have an encoding and:
Either encoding is US-ASCII compatible
One of the encodings is a 7-bit encoding
Iterates over the block according to how this Enumerator was constructed. If no block and no arguments are given, returns self.
"Hello, world!".scan(/\w+/) #=> ["Hello", "world"] "Hello, world!".to_enum(:scan, /\w+/).to_a #=> ["Hello", "world"] "Hello, world!".to_enum(:scan).each(/\w+/).to_a #=> ["Hello", "world"] obj = Object.new def obj.each_arg(a, b=:b, *rest) yield a yield b yield rest :method_returned end enum = obj.to_enum :each_arg, :a, :x enum.each.to_a #=> [:a, :x, []] enum.each.equal?(enum) #=> true enum.each { |elm| elm } #=> :method_returned enum.each(:y, :z).to_a #=> [:a, :x, [:y, :z]] enum.each(:y, :z).equal?(enum) #=> false enum.each(:y, :z) { |elm| elm } #=> :method_returned
The primary interface to this library. Use to setup delegation when defining your class.
class MyClass < DelegateClass(ClassToDelegateTo) # Step 1 def initialize super(obj_of_ClassToDelegateTo) # Step 2 end end
or:
MyClass = DelegateClass(ClassToDelegateTo) do # Step 1 def initialize super(obj_of_ClassToDelegateTo) # Step 2 end end
Here’s a sample of use from Tempfile which is really a File object with a few special rules about storage location and when the File should be deleted. That makes for an almost textbook perfect example of how to use delegation.
class Tempfile < DelegateClass(File) # constant and class member data initialization... def initialize(basename, tmpdir=Dir::tmpdir) # build up file path/name in var tmpname... @tmpfile = File.open(tmpname, File::RDWR|File::CREAT|File::EXCL, 0600) # ... super(@tmpfile) # below this point, all methods of File are supported... end # ... end
Return the status value associated with this system exit.
The first form is equivalent to attr_reader. The second form is equivalent to attr_accessor(name) but deprecated. The last form is equivalent to attr_reader(name) but deprecated. Returns an array of defined method names as symbols.
With no arguments, sets the default visibility for subsequently defined methods to private. With arguments, sets the named methods to have private visibility. String arguments are converted to symbols. An Array of Symbols and/or Strings is also accepted. If a single argument is passed, it is returned. If no argument is passed, nil is returned. If multiple arguments are passed, the arguments are returned as an array.
module Mod def a() end def b() end private def c() end private :a end Mod.private_instance_methods #=> [:a, :c]
Note that to show a private method on RDoc, use :doc:.
Returns the remainder from dividing by the value.
x.remainder(y) means x-y*(x/y).truncate
Truncate to the nearest integer (by default), returning the result as a BigDecimal.
BigDecimal('3.14159').truncate #=> 3 BigDecimal('8.7').truncate #=> 8 BigDecimal('-9.9').truncate #=> -9
If n is specified and positive, the fractional part of the result has no more than that many digits.
If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.
BigDecimal('3.14159').truncate(3) #=> 3.141 BigDecimal('13345.234').truncate(-2) #=> 13300.0
Returns the numerator.
Rational(7).numerator #=> 7 Rational(7, 1).numerator #=> 7 Rational(9, -4).numerator #=> -9 Rational(-2, -10).numerator #=> 1
Returns the denominator (always positive).
Rational(7).denominator #=> 1 Rational(7, 1).denominator #=> 1 Rational(9, -4).denominator #=> 4 Rational(-2, -10).denominator #=> 5
Returns true if rat is less than 0.
Returns the absolute value of rat.
(1/2r).abs #=> (1/2) (-1/2r).abs #=> (1/2)
Rational#magnitude is an alias for Rational#abs.
Returns rat truncated (toward zero) to a precision of ndigits decimal digits (default: 0).
When the precision is negative, the returned value is an integer with at least ndigits.abs trailing zeros.
Returns a rational when ndigits is positive, otherwise returns an integer.
Rational(3).truncate #=> 3 Rational(2, 3).truncate #=> 0 Rational(-3, 2).truncate #=> -1 # decimal - 1 2 3 . 4 5 6 # ^ ^ ^ ^ ^ ^ # precision -3 -2 -1 0 +1 +2 Rational('-123.456').truncate(+1).to_f #=> -123.4 Rational('-123.456').truncate(-1) #=> -120
Returns a simpler approximation of the value if the optional argument eps is given (rat-|eps| <= result <= rat+|eps|), self otherwise.
r = Rational(5033165, 16777216) r.rationalize #=> (5033165/16777216) r.rationalize(Rational('0.01')) #=> (3/10) r.rationalize(Rational('0.1')) #=> (1/3)
Returns a hash of values parsed from string, which should be a valid HTTP date format:
d = Date.new(2001, 2, 3) s = d.httpdate # => "Sat, 03 Feb 2001 00:00:00 GMT" Date._httpdate(s) # => {:wday=>6, :mday=>3, :mon=>2, :year=>2001, :hour=>0, :min=>0, :sec=>0, :zone=>"GMT", :offset=>0}
Related: Date.httpdate (returns a Date object).
Returns a new Date object with values parsed from string, which should be a valid HTTP date format:
d = Date.new(2001, 2, 3) s = d.httpdate # => "Sat, 03 Feb 2001 00:00:00 GMT" Date.httpdate(s) # => #<Date: 2001-02-03>
See:
Argument start.
Argument limit.
Related: Date._httpdate (returns a hash).
Returns true if self is a Saturday, false otherwise.
Equivalent to strftime with argument '%a, %d %b %Y %T GMT'; see Formats for Dates and Times:
Date.new(2001, 2, 3).httpdate # => "Sat, 03 Feb 2001 00:00:00 GMT"
Creates a new DateTime object by parsing from a string according to some RFC 2616 format.
DateTime.httpdate('Sat, 03 Feb 2001 04:05:06 GMT') #=> #<DateTime: 2001-02-03T04:05:06+00:00 ...>
Raise an ArgumentError when the string length is longer than limit. You can stop this check by passing limit: nil, but note that it may take a long time to parse.
Parses date as an HTTP-date defined by RFC 2616 and converts it to a Time object.
ArgumentError is raised if date is not compliant with RFC 2616 or if the Time class cannot represent specified date.
See httpdate for more information on this format.
require 'time' Time.httpdate("Thu, 06 Oct 2011 02:26:12 GMT") #=> 2011-10-06 02:26:12 UTC
You must require ‘time’ to use this method.
Returns a string which represents the time as RFC 1123 date of HTTP-date defined by RFC 2616:
day-of-week, DD month-name CCYY hh:mm:ss GMT
Note that the result is always UTC (GMT).
require 'time' t = Time.now t.httpdate # => "Thu, 06 Oct 2011 02:26:12 GMT"
You must require ‘time’ to use this method.
Returns a new Time object based the on given arguments, in the UTC timezone.
With one to seven arguments given, the arguments are interpreted as in the first calling sequence above:
Time.utc(year, month = 1, mday = 1, hour = 0, min = 0, sec = 0, usec = 0)
Examples:
Time.utc(2000) # => 2000-01-01 00:00:00 UTC Time.utc(-2000) # => -2000-01-01 00:00:00 UTC
There are no minimum and maximum values for the required argument year.
For the optional arguments:
month: Month in range (1..12), or case-insensitive 3-letter month name:
Time.utc(2000, 1) # => 2000-01-01 00:00:00 UTC Time.utc(2000, 12) # => 2000-12-01 00:00:00 UTC Time.utc(2000, 'jan') # => 2000-01-01 00:00:00 UTC Time.utc(2000, 'JAN') # => 2000-01-01 00:00:00 UTC
mday: Month day in range(1..31):
Time.utc(2000, 1, 1) # => 2000-01-01 00:00:00 UTC Time.utc(2000, 1, 31) # => 2000-01-31 00:00:00 UTC
hour: Hour in range (0..23), or 24 if min, sec, and usec are zero:
Time.utc(2000, 1, 1, 0) # => 2000-01-01 00:00:00 UTC Time.utc(2000, 1, 1, 23) # => 2000-01-01 23:00:00 UTC Time.utc(2000, 1, 1, 24) # => 2000-01-02 00:00:00 UTC
min: Minute in range (0..59):
Time.utc(2000, 1, 1, 0, 0) # => 2000-01-01 00:00:00 UTC Time.utc(2000, 1, 1, 0, 59) # => 2000-01-01 00:59:00 UTC
sec: Second in range (0..59), or 60 if usec is zero:
Time.utc(2000, 1, 1, 0, 0, 0) # => 2000-01-01 00:00:00 UTC Time.utc(2000, 1, 1, 0, 0, 59) # => 2000-01-01 00:00:59 UTC Time.utc(2000, 1, 1, 0, 0, 60) # => 2000-01-01 00:01:00 UTC
usec: Microsecond in range (0..999999):
Time.utc(2000, 1, 1, 0, 0, 0, 0) # => 2000-01-01 00:00:00 UTC Time.utc(2000, 1, 1, 0, 0, 0, 999999) # => 2000-01-01 00:00:00.999999 UTC
The values may be:
Integers, as above.
Numerics convertible to integers:
Time.utc(Float(0.0), Rational(1, 1), 1.0, 0.0, 0.0, 0.0, 0.0) # => 0000-01-01 00:00:00 UTC
String integers:
a = %w[0 1 1 0 0 0 0 0] # => ["0", "1", "1", "0", "0", "0", "0", "0"] Time.utc(*a) # => 0000-01-01 00:00:00 UTC
When exactly ten arguments are given, the arguments are interpreted as in the second calling sequence above:
Time.utc(sec, min, hour, mday, month, year, dummy, dummy, dummy, dummy)
where the dummy arguments are ignored:
a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] # => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] Time.utc(*a) # => 0005-04-03 02:01:00 UTC
This form is useful for creating a Time object from a 10-element array returned by Time.to_a:
t = Time.new(2000, 1, 2, 3, 4, 5, 6) # => 2000-01-02 03:04:05 +000006 a = t.to_a # => [5, 4, 3, 2, 1, 2000, 0, 2, false, nil] Time.utc(*a) # => 2000-01-02 03:04:05 UTC
The two forms have their first six arguments in common, though in different orders; the ranges of these common arguments are the same for both forms; see above.
Raises an exception if the number of arguments is eight, nine, or greater than ten.
Time.gm is an alias for Time.utc.
Related: Time.local.
Returns self, converted to the UTC timezone:
t = Time.new(2000) # => 2000-01-01 00:00:00 -0600 t.utc? # => false t.utc # => 2000-01-01 06:00:00 UTC t.utc? # => true
Time#gmtime is an alias for Time#utc.
Related: Time#getutc (returns a new converted Time object).