Returns nil. Just for compatibility to IO.
Returns the size of the buffer string.
Returns the default value for the given key. The returned value will be determined either by the default proc or by the default value. See Hash Default.
With no argument, returns the current default value:
h = {} h.default # => nil
If key is given, returns the default value for key, regardless of whether that key exists:
h = Hash.new { |hash, key| hash[key] = "No key #{key}"} h[:foo] = "Hello" h.default(:foo) # => "No key foo"
Sets the default value to value; returns value:
h = {} h.default # => nil h.default = false # => false h.default # => false
See Hash Default.
Returns the count of entries in self:
{foo: 0, bar: 1, baz: 2}.size # => 3
Related: see Methods for Querying.
If an entry for the given key is found, deletes the entry and returns its associated value; otherwise returns nil or calls the given block.
With no block given and key found, deletes the entry and returns its value:
h = {foo: 0, bar: 1, baz: 2} h.delete(:bar) # => 1 h # => {foo: 0, baz: 2}
With no block given and key not found, returns nil.
With a block given and key found, ignores the block, deletes the entry, and returns its value:
h = {foo: 0, bar: 1, baz: 2} h.delete(:baz) { |key| raise 'Will never happen'} # => 2 h # => {foo: 0, bar: 1}
With a block given and key not found, calls the block and returns the block’s return value:
h = {foo: 0, bar: 1, baz: 2} h.delete(:nosuch) { |key| "Key #{key} not found" } # => "Key nosuch not found" h # => {foo: 0, bar: 1, baz: 2}
Related: see Methods for Deleting.
Deletes the environment variable with name if it exists and returns its value:
ENV['foo'] = '0' ENV.delete('foo') # => '0'
If a block is not given and the named environment variable does not exist, returns nil.
If a block given and the environment variable does not exist, yields name to the block and returns the value of the block:
ENV.delete('foo') { |name| name * 2 } # => "foofoo"
If a block given and the environment variable exists, deletes the environment variable and returns its value (ignoring the block):
ENV['foo'] = '0' ENV.delete('foo') { |name| raise 'ignored' } # => "0"
Raises an exception if name is invalid. See Invalid Names and Values.
Removes every environment variable; returns ENV:
ENV.replace('foo' => '0', 'bar' => '1') ENV.size # => 2 ENV.clear # => ENV ENV.size # => 0
Returns the count of environment variables:
ENV.replace('foo' => '0', 'bar' => '1') ENV.length # => 2 ENV.size # => 2
Returns an integer representing the numeric file descriptor for the current file. Raises an ArgumentError if there isn’t a current file.
ARGF.fileno #=> 3
Returns the current filename. “-” is returned when the current file is STDIN.
For example:
$ echo "foo" > foo $ echo "bar" > bar $ echo "glark" > glark $ ruby argf.rb foo bar glark ARGF.filename #=> "foo" ARGF.read(5) #=> "foo\nb" ARGF.filename #=> "bar" ARGF.skip ARGF.filename #=> "glark"
Returns the current file as an IO or File object. $stdin is returned when the current file is STDIN.
For example:
$ echo "foo" > foo $ echo "bar" > bar $ ruby argf.rb foo bar ARGF.file #=> #<File:foo> ARGF.read(5) #=> "foo\nb" ARGF.file #=> #<File:bar>
Returns the methods available to this delegate object as the union of this object’s and _getobj_ methods.
Executes the generated ERB code to produce a completed template, returning the results of that code.
b accepts a Binding object which is used to set the context of code evaluation.
Release code
Removes the last List.
Returns size of the match array:
m = /(.)(.)(\d+)(\d)/.match("THX1138.") # => #<MatchData "HX1138" 1:"H" 2:"X" 3:"113" 4:"8"> m.size # => 5
This says “you can break a line here if necessary”, and a width-column text sep is inserted if a line is not broken at the point.
If sep is not specified, “ ” is used.
If width is not specified, sep.length is used. You will have to specify this when sep is a multibyte character, for example.
Checks if the object is shareable by ractors.
Ractor.shareable?(1) #=> true -- numbers and other immutable basic values are frozen Ractor.shareable?('foo') #=> false, unless the string is frozen due to # frozen_string_literal: true Ractor.shareable?('foo'.freeze) #=> true
See also the “Shareable and unshareable objects” section in the Ractor class docs.
Activates the trace.
Returns true if the trace was enabled. Returns false if the trace was disabled.
trace.enabled? #=> false trace.enable #=> false (previous state) # trace is enabled trace.enabled? #=> true trace.enable #=> true (previous state) # trace is still enabled
If a block is given, the trace will only be enabled during the block execution. If target and target_line are both nil, then target_thread will default to the current thread if a block is given.
trace.enabled? #=> false trace.enable do trace.enabled? # Only enabled for this block and thread end trace.enabled? #=> false
The target, target_line, and target_thread parameters are used to limit tracing to specified code objects. target should be a code object for which RubyVM::InstructionSequence.of will return an instruction sequence.
t = TracePoint.new(:line) { |tp| p tp } def m1 p 1 end def m2 p 2 end t.enable(target: method(:m1)) m1 # Prints #<TracePoint:line test.rb:4 in `m1'> m2 # Prints nothing
Note: You cannot access event hooks within the enable block.
trace.enable { p tp.lineno } #=> RuntimeError: access from outside