Returns true if the named file is writable by the effective user and group id of this process. See eaccess(3).
Note that some OS-level security features may cause this to return true even though the file is not writable by the effective user/group.
Returns true if filepath points to a pipe, false otherwise:
File.mkfifo('tmp/fifo') File.pipe?('tmp/fifo') # => true File.pipe?('t.txt') # => false
Returns the list of loaded encodings.
Encoding.list #=> [#<Encoding:ASCII-8BIT>, #<Encoding:UTF-8>, #<Encoding:ISO-2022-JP (dummy)>] Encoding.find("US-ASCII") #=> #<Encoding:US-ASCII> Encoding.list #=> [#<Encoding:ASCII-8BIT>, #<Encoding:UTF-8>, #<Encoding:US-ASCII>, #<Encoding:ISO-2022-JP (dummy)>]
Returns a Digest subclass by name in a thread-safe manner even when on-demand loading is involved.
require 'digest' Digest("MD5") # => Digest::MD5 Digest(:SHA256) # => Digest::SHA256 Digest(:Foo) # => LoadError: library not found for class Digest::Foo -- digest/foo
Returns any backtrace associated with the exception. The backtrace is an array of strings, each containing either “filename:lineNo: in ‘method”’ or “filename:lineNo.”
def a raise "boom" end def b a() end begin b() rescue => detail print detail.backtrace.join("\n") end
produces:
prog.rb:2:in `a' prog.rb:6:in `b' prog.rb:10
In the case no backtrace has been set, nil is returned
ex = StandardError.new ex.backtrace #=> nil
Return the status value associated with this system exit.
Returns the list of Modules nested at the point of call.
module M1 module M2 $a = Module.nesting end end $a #=> [M1::M2, M1] $a[0].name #=> "M1::M2"
In the first form, returns an array of the names of all constants accessible from the point of call. This list includes the names of all modules and classes defined in the global scope.
Module.constants.first(4) # => [:ARGF, :ARGV, :ArgumentError, :Array] Module.constants.include?(:SEEK_SET) # => false class IO Module.constants.include?(:SEEK_SET) # => true end
The second form calls the instance method constants.
Returns a list of modules included/prepended in mod (including mod itself).
module Mod include Math include Comparable prepend Enumerable end Mod.ancestors #=> [Enumerable, Mod, Comparable, Math] Math.ancestors #=> [Math] Enumerable.ancestors #=> [Enumerable]
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.
Returns an array of the names of the constants accessible in mod. This includes the names of constants in any included modules (example at start of section), unless the inherit parameter is set to false.
The implementation makes no guarantees about the order in which the constants are yielded.
IO.constants.include?(:SYNC) #=> true IO.constants(false).include?(:SYNC) #=> false
Also see Module#const_defined?.
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:.
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 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
Synonym for $stdin.
Synonym for $stdout.
Print an argument or list of arguments to the default output stream
cgi = CGI.new cgi.print # default: cgi.print == $DEFAULT_OUTPUT.print
Returns true if self is a Friday, false otherwise.
Returns true if the date is on or after the date of calendar reform, false otherwise:
Date.new(1582, 10, 15).gregorian? # => true (Date.new(1582, 10, 15) - 1).gregorian? # => false
Returns the Julian start date for calendar reform; if not an infinity, the returned value is suitable for passing to Date#jd:
d = Date.new(2001, 2, 3, Date::ITALY) s = d.start # => 2299161.0 Date.jd(s).to_s # => "1582-10-15" d = Date.new(2001, 2, 3, Date::ENGLAND) s = d.start # => 2361222.0 Date.jd(s).to_s # => "1752-09-14" Date.new(2001, 2, 3, Date::GREGORIAN).start # => -Infinity Date.new(2001, 2, 3, Date::JULIAN).start # => Infinity
See argument start.
Equivalent to Date#new_start with argument Date::GREGORIAN.
Calls the block with specified dates; returns self.
The first date is self.
Each successive date is date + step, where step is the numeric step size in days.
The last date is the last one that is before or equal to limit, which should be a Date object.
Example:
limit = Date.new(2001, 12, 31) Date.new(2001).step(limit){|date| p date.to_s if date.mday == 31 }
Output:
"2001-01-31" "2001-03-31" "2001-05-31" "2001-07-31" "2001-08-31" "2001-10-31" "2001-12-31"
Returns an Enumerator if no block is given.
Returns true if self is in daylight saving time, false otherwise:
t = Time.local(2000, 1, 1) # => 2000-01-01 00:00:00 -0600 t.zone # => "Central Standard Time" t.dst? # => false t = Time.local(2000, 7, 1) # => 2000-07-01 00:00:00 -0500 t.zone # => "Central Daylight Time" t.dst? # => true
Time#isdst is an alias for Time#dst?.
Returns true if self is in daylight saving time, false otherwise:
t = Time.local(2000, 1, 1) # => 2000-01-01 00:00:00 -0600 t.zone # => "Central Standard Time" t.dst? # => false t = Time.local(2000, 7, 1) # => 2000-07-01 00:00:00 -0500 t.zone # => "Central Daylight Time" t.dst? # => true
Time#isdst is an alias for Time#dst?.