Closes the stream for both reading and writing if open for either or both; returns nil. See Open and Closed Streams.
If the stream is open for writing, flushes any buffered writes to the operating system before closing.
If the stream was opened by IO.popen, sets global variable $? (child exit status).
It is not an error to close an IO object that has already been closed. It just returns nil.
Example:
IO.popen('ruby', 'r+') do |pipe| puts pipe.closed? pipe.close puts $? puts pipe.closed? end
Output:
false pid 13760 exit 0 true
Related: IO#close_read, IO#close_write, IO#closed?.
Returns true if the stream is closed for both reading and writing, false otherwise. See Open and Closed Streams.
IO.popen('ruby', 'r+') do |pipe| puts pipe.closed? pipe.close_read puts pipe.closed? pipe.close_write puts pipe.closed? end
Output:
false false true
Related: IO#close_read, IO#close_write, IO#close.
Returns true if the underlying file descriptor of ios will be closed at its finalization or at calling close, otherwise false.
Sets auto-close flag.
f = File.open(File::NULL) IO.for_fd(f.fileno).close f.gets # raises Errno::EBADF f = File.open(File::NULL) g = IO.for_fd(f.fileno) g.autoclose = false g.close f.gets # won't cause Errno::EBADF
Returns true if object is an element of self, false otherwise:
(1..4).include?(2) # => true (1..4).include?(5) # => false (1..4).include?(4) # => true (1...4).include?(4) # => false ('a'..'d').include?('b') # => true ('a'..'d').include?('e') # => false ('a'..'d').include?('B') # => false ('a'..'d').include?('d') # => true ('a'...'d').include?('d') # => false
If begin and end are numeric, include? behaves like cover?
(1..3).include?(1.5) # => true (1..3).cover?(1.5) # => true
But when not numeric, the two methods may differ:
('a'..'d').include?('cc') # => false ('a'..'d').cover?('cc') # => true
Related: Range#cover?.
Returns true if the given argument is within self, false otherwise.
With non-range argument object, evaluates with <= and <.
For range self with included end value (exclude_end? == false), evaluates thus:
self.begin <= object <= self.end
Examples:
r = (1..4) r.cover?(1) # => true r.cover?(4) # => true r.cover?(0) # => false r.cover?(5) # => false r.cover?('foo') # => false r = ('a'..'d') r.cover?('a') # => true r.cover?('d') # => true r.cover?(' ') # => false r.cover?('e') # => false r.cover?(0) # => false
For range r with excluded end value (exclude_end? == true), evaluates thus:
r.begin <= object < r.end
Examples:
r = (1...4) r.cover?(1) # => true r.cover?(3) # => true r.cover?(0) # => false r.cover?(4) # => false r.cover?('foo') # => false r = ('a'...'d') r.cover?('a') # => true r.cover?('c') # => true r.cover?(' ') # => false r.cover?('d') # => false r.cover?(0) # => false
With range argument range, compares the first and last elements of self and range:
r = (1..4) r.cover?(1..4) # => true r.cover?(0..4) # => false r.cover?(1..5) # => false r.cover?('a'..'d') # => false r = (1...4) r.cover?(1..3) # => true r.cover?(1..4) # => false
If begin and end are numeric, cover? behaves like include?
(1..3).cover?(1.5) # => true (1..3).include?(1.5) # => true
But when not numeric, the two methods may differ:
('a'..'d').cover?('cc') # => true ('a'..'d').include?('cc') # => false
Returns false if either:
The begin value of self is larger than its end value.
An internal call to <=> returns nil; that is, the operands are not comparable.
Beginless ranges cover all values of the same type before the end, excluding the end for exclusive ranges. Beginless ranges cover ranges that end before the end of the beginless range, or at the end of the beginless range for inclusive ranges.
(..2).cover?(1) # => true (..2).cover?(2) # => true (..2).cover?(3) # => false (...2).cover?(2) # => false (..2).cover?("2") # => false (..2).cover?(..2) # => true (..2).cover?(...2) # => true (..2).cover?(.."2") # => false (...2).cover?(..2) # => false
Endless ranges cover all values of the same type after the beginning. Endless exclusive ranges do not cover endless inclusive ranges.
(2..).cover?(1) # => false (2..).cover?(3) # => true (2...).cover?(3) # => true (2..).cover?(2) # => true (2..).cover?("2") # => false (2..).cover?(2..) # => true (2..).cover?(2...) # => true (2..).cover?("2"..) # => false (2...).cover?(2..) # => false (2...).cover?(3...) # => true (2...).cover?(3..) # => false (3..).cover?(2..) # => false
Ranges that are both beginless and endless cover all values and ranges, and return true for all arguments, with the exception that beginless and endless exclusive ranges do not cover endless inclusive ranges.
(nil...).cover?(Object.new) # => true (nil...).cover?(nil...) # => true (nil..).cover?(nil...) # => true (nil...).cover?(nil..) # => false (nil...).cover?(1..) # => false
Related: Range#include?.
Returns true if range overlaps with self, false otherwise:
(0..2).overlap?(1..3) #=> true (0..2).overlap?(3..4) #=> false (0..).overlap?(..0) #=> true
With non-range argument, raises TypeError.
(1..3).overlap?(1) # TypeError
Returns false if an internal call to <=> returns nil; that is, the operands are not comparable.
(1..3).overlap?('a'..'d') # => false
Returns false if self or range is empty. “Empty range” means that its begin value is larger than, or equal for an exclusive range, its end value.
(4..1).overlap?(2..3) # => false (4..1).overlap?(..3) # => false (4..1).overlap?(2..) # => false (2...2).overlap?(1..2) # => false (1..4).overlap?(3..2) # => false (..4).overlap?(3..2) # => false (1..).overlap?(3..2) # => false (1..2).overlap?(2...2) # => false
Returns false if the begin value one of self and range is larger than, or equal if the other is an exclusive range, the end value of the other:
(4..5).overlap?(2..3) # => false (4..5).overlap?(2...4) # => false (1..2).overlap?(3..4) # => false (1...3).overlap?(3..4) # => false
Returns false if the end value one of self and range is larger than, or equal for an exclusive range, the end value of the other:
(4..5).overlap?(2..3) # => false (4..5).overlap?(2...4) # => false (1..2).overlap?(3..4) # => false (1...3).overlap?(3..4) # => false
Note that the method wouldn’t make any assumptions about the beginless range being actually empty, even if its upper bound is the minimum possible value of its type, so all this would return true:
(...-Float::INFINITY).overlap?(...-Float::INFINITY) # => true (..."").overlap?(..."") # => true (...[]).overlap?(...[]) # => true
Even if those ranges are effectively empty (no number can be smaller than -Float::INFINITY), they are still considered overlapping with themselves.
Related: Range#cover?.
Returns the numerator.
Rational(7).numerator #=> 7 Rational(7, 1).numerator #=> 7 Rational(9, -4).numerator #=> -9 Rational(-2, -10).numerator #=> 1
Returns the largest number less than or equal to rat with 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).floor #=> 3 Rational(2, 3).floor #=> 0 Rational(-3, 2).floor #=> -2 # decimal - 1 2 3 . 4 5 6 # ^ ^ ^ ^ ^ ^ # precision -3 -2 -1 0 +1 +2 Rational('-123.456').floor(+1).to_f #=> -123.5 Rational('-123.456').floor(-1) #=> -130
Returns true if the set is a superset of the given set.
Returns true if the set and the given enumerable have at least one element in common.
Set[1, 2, 3].intersect? Set[4, 5] #=> false Set[1, 2, 3].intersect? Set[3, 4] #=> true Set[1, 2, 3].intersect? 4..5 #=> false Set[1, 2, 3].intersect? [3, 4] #=> true
Equivalent to Set#select!
Returns the member names of the Struct descendant as an array:
Customer = Struct.new(:name, :address, :zip) Customer.members # => [:name, :address, :zip]
With a block given, returns an array of values from self for which the block returns a truthy value:
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) a = joe.select {|value| value.is_a?(String) } a # => ["Joe Smith", "123 Maple, Anytown NC"] a = joe.select {|value| value.is_a?(Integer) } a # => [12345]
With no block given, returns an Enumerator.
Returns the member names from self as an array:
Customer = Struct.new(:name, :address, :zip) Customer.new.members # => [:name, :address, :zip]
Related: to_a.
Callback invoked whenever a subclass of the current class is created.
Example:
class Foo def self.inherited(subclass) puts "New subclass: #{subclass}" end end class Bar < Foo end class Baz < Bar end
produces:
New subclass: Bar New subclass: Baz
Allocates space for a new object of class’s class and does not call initialize on the new instance. The returned object must be an instance of class.
klass = Class.new do def initialize(*args) @initialized = true end def initialized? @initialized || false end end klass.allocate.initialized? #=> false
Returns the superclass of class, or nil.
File.superclass #=> IO IO.superclass #=> Object Object.superclass #=> BasicObject class Foo; end class Bar < Foo; end Bar.superclass #=> Foo
Returns nil when the given class does not have a parent class:
BasicObject.superclass #=> nil
Enters exclusive section.