Looks up the first IP address for name.
Looks up all IP address for name.
Returns the full path name of the temporary file. This will be nil if unlink has been called.
Creates a file in the underlying file system; returns a new File object based on that file.
With no block given and no arguments, creates and returns file whose:
Directory is the system temporary directory (system-dependent).
Generated filename is unique in that directory.
Permissions are 0600; see File Permissions.
Mode is 'w+' (read/write mode, positioned at the end).
With no block, the file is not removed automatically, and so should be explicitly removed.
Example:
f = Tempfile.create # => #<File:/tmp/20220505-9795-17ky6f6> f.class # => File f.path # => "/tmp/20220505-9795-17ky6f6" f.stat.mode.to_s(8) # => "100600" File.exist?(f.path) # => true File.unlink(f.path) File.exist?(f.path) # => false
Argument basename, if given, may be one of:
A string: the generated filename begins with basename:
Tempfile.create('foo') # => #<File:/tmp/foo20220505-9795-1gok8l9>
An array of two strings [prefix, suffix]: the generated filename begins with prefix and ends with suffix:
Tempfile.create(%w/foo .jpg/) # => #<File:/tmp/foo20220505-17839-tnjchh.jpg>
With arguments basename and tmpdir, the file is created in directory tmpdir:
Tempfile.create('foo', '.') # => #<File:./foo20220505-9795-1emu6g8>
Keyword arguments mode and options are passed directly to method File.open:
The value given with mode must be an integer, and may be expressed as the logical OR of constants defined in File::Constants.
For options, see Open Options.
With a block given, creates the file as above, passes it to the block, and returns the block’s value; before the return, the file object is closed and the underlying file is removed:
Tempfile.create {|file| file.path } # => "/tmp/20220505-9795-rkists"
Related: Tempfile.new.
Returns true if a Proc object is lambda. false if non-lambda.
The lambda-ness affects argument handling and the behavior of return and break.
A Proc object generated by proc ignores extra arguments.
proc {|a,b| [a,b] }.call(1,2,3) #=> [1,2]
It provides nil for missing arguments.
proc {|a,b| [a,b] }.call(1) #=> [1,nil]
It expands a single array argument.
proc {|a,b| [a,b] }.call([1,2]) #=> [1,2]
A Proc object generated by lambda doesn’t have such tricks.
lambda {|a,b| [a,b] }.call(1,2,3) #=> ArgumentError lambda {|a,b| [a,b] }.call(1) #=> ArgumentError lambda {|a,b| [a,b] }.call([1,2]) #=> ArgumentError
Proc#lambda? is a predicate for the tricks. It returns true if no tricks apply.
lambda {}.lambda? #=> true proc {}.lambda? #=> false
Proc.new is the same as proc.
Proc.new {}.lambda? #=> false
lambda, proc and Proc.new preserve the tricks of a Proc object given by & argument.
lambda(&lambda {}).lambda? #=> true proc(&lambda {}).lambda? #=> true Proc.new(&lambda {}).lambda? #=> true lambda(&proc {}).lambda? #=> false proc(&proc {}).lambda? #=> false Proc.new(&proc {}).lambda? #=> false
A Proc object generated by & argument has the tricks
def n(&b) b.lambda? end n {} #=> false
The & argument preserves the tricks if a Proc object is given by & argument.
n(&lambda {}) #=> true n(&proc {}) #=> false n(&Proc.new {}) #=> false
A Proc object converted from a method has no tricks.
def m() end method(:m).to_proc.lambda? #=> true n(&method(:m)) #=> true n(&method(:m).to_proc) #=> true
define_method is treated the same as method definition. The defined method has no tricks.
class C define_method(:d) {} end C.new.d(1,2) #=> ArgumentError C.new.method(:d).to_proc.lambda? #=> true
define_method always defines a method without the tricks, even if a non-lambda Proc object is given. This is the only exception for which the tricks are not preserved.
class C define_method(:e, &proc {}) end C.new.e(1,2) #=> ArgumentError C.new.method(:e).to_proc.lambda? #=> true
This exception ensures that methods never have tricks and makes it easy to have wrappers to define methods that behave as usual.
class C def self.def2(name, &body) define_method(name, &body) end def2(:f) {} end C.new.f(1,2) #=> ArgumentError
The wrapper def2 defines a method which has no tricks.
Get a message from the ractor’s outgoing port, which was put there by Ractor.yield or at ractor’s termination.
r = Ractor.new do Ractor.yield 'explicit yield' 'last value' end puts r.take #=> 'explicit yield' puts r.take #=> 'last value' puts r.take # Ractor::ClosedError (The outgoing-port is already closed)
The fact that the last value is also sent to the outgoing port means that take can be used as an analog of Thread#join (“just wait until ractor finishes”). However, it will raise if somebody has already consumed that message.
If the outgoing port was closed with close_outgoing, the method will raise Ractor::ClosedError.
r = Ractor.new do sleep(500) Ractor.yield 'Hello from ractor' end r.close_outgoing r.take # Ractor::ClosedError (The outgoing-port is already closed) # The error would be raised immediately, not when ractor will try to receive
If an uncaught exception is raised in the Ractor, it is propagated by take as a Ractor::RemoteError.
r = Ractor.new {raise "Something weird happened"} begin r.take rescue => e p e # => #<Ractor::RemoteError: thrown by remote Ractor.> p e.ractor == r # => true p e.cause # => #<RuntimeError: Something weird happened> end
Ractor::ClosedError is a descendant of StopIteration, so the termination of the ractor will break out of any loops that receive this message without propagating the error:
r = Ractor.new do 3.times {|i| Ractor.yield "message #{i}"} "finishing" end loop {puts "Received: " + r.take} puts "Continue successfully"
This will print:
Received: message 0 Received: message 1 Received: message 2 Received: finishing Continue successfully
Basically the same as ::new. However, if class Thread is subclassed, then calling start in that subclass will not invoke the subclass’s initialize method.
Terminates thr and schedules another thread to be run, returning the terminated Thread. If this is the main thread, or the last thread, exits the process.
Path of the file being run
Return the tag object which was called for.
Creates a new Pathname object from the given string, path, and returns pathname object.
In order to use this constructor, you must first require the Pathname standard library extension.
require 'pathname' Pathname("/home/zzak") #=> #<Pathname:/home/zzak>
See also Pathname::new for more information.
Yields self to the block, and then returns self. The primary purpose of this method is to “tap into” a method chain, in order to perform operations on intermediate results within the chain.
(1..10) .tap {|x| puts "original: #{x}" } .to_a .tap {|x| puts "array: #{x}" } .select {|x| x.even? } .tap {|x| puts "evens: #{x}" } .map {|x| x*x } .tap {|x| puts "squares: #{x}" }
Returns arg converted to a float. Numeric types are converted directly, and with exception to String and nil the rest are converted using arg.to_f. Converting a String with invalid characters will result in a ArgumentError. Converting nil generates a TypeError. Exceptions can be suppressed by passing exception: false.
Float(1) #=> 1.0 Float("123.456") #=> 123.456 Float("123.0_badstring") #=> ArgumentError: invalid value for Float(): "123.0_badstring" Float(nil) #=> TypeError: can't convert nil into Float Float("123.0_badstring", exception: false) #=> nil
Returns the string resulting from formatting objects into format_string.
For details on format_string, see Format Specifications.
Equivalent to Proc.new, except the resulting Proc objects check the number of parameters passed when called.
Returns x/y or arg as a Rational.
Rational(2, 3) #=> (2/3) Rational(5) #=> (5/1) Rational(0.5) #=> (1/2) Rational(0.3) #=> (5404319552844595/18014398509481984) Rational("2/3") #=> (2/3) Rational("0.3") #=> (3/10) Rational("10 cents") #=> ArgumentError Rational(nil) #=> TypeError Rational(1, nil) #=> TypeError Rational("10 cents", exception: false) #=> nil
Syntax of the string form:
string form = extra spaces , rational , extra spaces ;
rational = [ sign ] , unsigned rational ;
unsigned rational = numerator | numerator , "/" , denominator ;
numerator = integer part | fractional part | integer part , fractional part ;
denominator = digits ;
integer part = digits ;
fractional part = "." , digits , [ ( "e" | "E" ) , [ sign ] , digits ] ;
sign = "-" | "+" ;
digits = digit , { digit | "_" , digit } ;
digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
extra spaces = ? \s* ? ;
See also String#to_r.
Deprecated. Use block_given? instead.
catch executes its block. If throw is not called, the block executes normally, and catch returns the value of the last expression evaluated.
catch(1) { 123 } # => 123
If throw(tag2, val) is called, Ruby searches up its stack for a catch block whose tag has the same object_id as tag2. When found, the block stops executing and returns val (or nil if no second argument was given to throw).
catch(1) { throw(1, 456) } # => 456 catch(1) { throw(1) } # => nil
When tag is passed as the first argument, catch yields it as the parameter of the block.
catch(1) {|x| x + 2 } # => 3
When no tag is given, catch yields a new unique object (as from Object.new) as the block parameter. This object can then be used as the argument to throw, and will match the correct catch block.
catch do |obj_A| catch do |obj_B| throw(obj_B, 123) puts "This puts is not reached" end puts "This puts is displayed" 456 end # => 456 catch do |obj_A| catch do |obj_B| throw(obj_A, 123) puts "This puts is still not reached" end puts "Now this puts is also not reached" 456 end # => 123
Returns a hash containing the counts of equal elements:
Each key is an element of self.
Each value is the number elements equal to that key.
With no argument:
%w[a b c b c a c b].tally # => {"a"=>2, "b"=>3, "c"=>3}
With a hash argument, that hash is used for the tally (instead of a new hash), and is returned; this may be useful for accumulating tallies across multiple enumerables:
hash = {} hash = %w[a c d b c a].tally(hash) hash # => {"a"=>2, "c"=>2, "d"=>1, "b"=>1} hash = %w[b a z].tally(hash) hash # => {"a"=>3, "c"=>2, "d"=>1, "b"=>2, "z"=>1} hash = %w[b a m].tally(hash) hash # => {"a"=>4, "c"=>2, "d"=>1, "b"=>3, "z"=>1, "m"=> 1}
For non-negative integer n, returns the first n elements:
r = (1..4) r.take(2) # => [1, 2] r.take(0) # => [] h = {foo: 0, bar: 1, baz: 2, bat: 3} h.take(2) # => [[:foo, 0], [:bar, 1]]
Returns a list of the supported category symbols.
Enables the coverage measurement. See the documentation of Coverage class in detail. This is equivalent to Coverage.setup and Coverage.resume.
Returns a String containing the generated JSON data.
See also JSON.fast_generate, JSON.pretty_generate.
Argument obj is the Ruby object to be converted to JSON.
Argument opts, if given, contains a Hash of options for the generation. See Generating Options.
When obj is an Array, returns a String containing a JSON array:
obj = ["foo", 1.0, true, false, nil] json = JSON.generate(obj) json # => '["foo",1.0,true,false,null]'
When obj is a Hash, returns a String containing a JSON object:
obj = {foo: 0, bar: 's', baz: :bat} json = JSON.generate(obj) json # => '{"foo":0,"bar":"s","baz":"bat"}'
For examples of generating from other Ruby objects, see Generating JSON from Other Objects.
Raises an exception if any formatting option is not a String.
Raises an exception if obj contains circular references:
a = []; b = []; a.push(b); b.push(a) # Raises JSON::NestingError (nesting of 100 is too deep): JSON.generate(a)
Compresses the given string. Valid values of level are Zlib::NO_COMPRESSION, Zlib::BEST_SPEED, Zlib::BEST_COMPRESSION, Zlib::DEFAULT_COMPRESSION, or an integer from 0 to 9.
This method is almost equivalent to the following code:
def deflate(string, level) z = Zlib::Deflate.new(level) dst = z.deflate(string, Zlib::FINISH) z.close dst end
See also Zlib.inflate
Decompresses string. Raises a Zlib::NeedDict exception if a preset dictionary is needed for decompression.
This method is almost equivalent to the following code:
def inflate(string) zstream = Zlib::Inflate.new buf = zstream.inflate(string) zstream.finish zstream.close buf end
See also Zlib.deflate