When invoked with a block, yield all repeated permutations of length n
of the elements of the array, then return the array itself.
The implementation makes no guarantees about the order in which the repeated permutations are yielded.
If no block is given, an Enumerator
is returned instead.
Examples:
a = [1, 2] a.repeated_permutation(1).to_a #=> [[1], [2]] a.repeated_permutation(2).to_a #=> [[1,1],[1,2],[2,1],[2,2]] a.repeated_permutation(3).to_a #=> [[1,1,1],[1,1,2],[1,2,1],[1,2,2], # [2,1,1],[2,1,2],[2,2,1],[2,2,2]] a.repeated_permutation(0).to_a #=> [[]] # one permutation of length 0
Returns true
if obj responds to the given method. Private and protected methods are included in the search only if the optional second parameter evaluates to true
.
If the method is not implemented, as Process.fork
on Windows, File.lchmod
on GNU/Linux, etc., false is returned.
If the method is not defined, respond_to_missing?
method is called and the result is returned.
When the method name parameter is given as a string, the string is converted to a symbol.
Returns an array of grapheme clusters in str. This is a shorthand for str.each_grapheme_cluster.to_a
.
If a block is given, which is a deprecated form, works the same as each_grapheme_cluster
.
Deserializes JSON
string by constructing new Exception
object with message m
and backtrace b
serialized with to_json
Creates module functions for the named methods. These functions may be called with the module as a receiver, and also become available as instance methods to classes that mix in the module. Module
functions are copies of the original, and so may be changed independently. The instance-method versions are made private. If used with no arguments, subsequently defined methods become module functions. String arguments are converted to symbols.
module Mod def one "This is one" end module_function :one end class Cls include Mod def call_one one end end Mod.one #=> "This is one" c = Cls.new c.call_one #=> "This is one" module Mod def one "This is the new one" end end Mod.one #=> "This is one" c.call_one #=> "This is the new one"
Deserializes JSON
string by converting numerator value n
, denominator value d
, to a Rational
object.
Deserializes JSON
string by converting Julian year y
, month m
, day d
and Day of Calendar Reform sg
to Date
.
Deserializes JSON
string by converting year y
, month m
, day d
, hour H
, minute M
, second S
, offset of
and Day of Calendar Reform sg
to DateTime
.
Reads at most maxlen bytes from ios using the read(2) system call after O_NONBLOCK is set for the underlying file descriptor.
If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
read_nonblock
just calls the read(2) system call. It causes all errors the read(2) system call causes: Errno::EWOULDBLOCK, Errno::EINTR, etc. The caller should care such errors.
If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitReadable
. So IO::WaitReadable
can be used to rescue the exceptions for retrying read_nonblock.
read_nonblock
causes EOFError
on EOF.
If the read byte buffer is not empty, read_nonblock
reads from the buffer like readpartial. In this case, the read(2) system call is not called.
When read_nonblock
raises an exception kind of IO::WaitReadable
, read_nonblock
should not be called until io is readable for avoiding busy loop. This can be done as follows.
# emulates blocking read (readpartial). begin result = io.read_nonblock(maxlen) rescue IO::WaitReadable IO.select([io]) retry end
Although IO#read_nonblock
doesn’t raise IO::WaitWritable
. OpenSSL::Buffering#read_nonblock
can raise IO::WaitWritable
. If IO
and SSL should be used polymorphically, IO::WaitWritable
should be rescued too. See the document of OpenSSL::Buffering#read_nonblock
for sample code.
Note that this method is identical to readpartial except the non-blocking flag is set.
By specifying a keyword argument exception to false
, you can indicate that read_nonblock
should not raise an IO::WaitReadable
exception, but return the symbol :wait_readable
instead. At EOF, it will return nil instead of raising EOFError
.
Deserializes JSON
string by constructing new Regexp
object with source s
(Regexp
or String) and options o
serialized by to_json
Returns true if this class can be used to create an instance from a serialised JSON
string. The class has to implement a class method json_create that expects a hash as first parameter. The hash should include the required data.
Receives up to maxlen bytes from socket
using recvfrom(2) after O_NONBLOCK is set for the underlying file descriptor. flags is zero or more of the MSG_
options. The first element of the results, mesg, is the data received. The second element, sender_addrinfo, contains protocol-specific address information of the sender.
When recvfrom(2) returns 0, Socket#recvfrom_nonblock
returns an empty string as data. The meaning depends on the socket: EOF on TCP, empty packet on UDP, etc.
maxlen
- the maximum number of bytes to receive from the socket
flags
- zero or more of the MSG_
options
outbuf
- destination String buffer
opts
- keyword hash, supporting ‘exception: false`
# In one file, start this first require 'socket' include Socket::Constants socket = Socket.new(AF_INET, SOCK_STREAM, 0) sockaddr = Socket.sockaddr_in(2200, 'localhost') socket.bind(sockaddr) socket.listen(5) client, client_addrinfo = socket.accept begin # emulate blocking recvfrom pair = client.recvfrom_nonblock(20) rescue IO::WaitReadable IO.select([client]) retry end data = pair[0].chomp puts "I only received 20 bytes '#{data}'" sleep 1 socket.close # In another file, start this second require 'socket' include Socket::Constants socket = Socket.new(AF_INET, SOCK_STREAM, 0) sockaddr = Socket.sockaddr_in(2200, 'localhost') socket.connect(sockaddr) socket.puts "Watch this get cut short!" socket.close
Refer to Socket#recvfrom
for the exceptions that may be thrown if the call to recvfrom_nonblock fails.
Socket#recvfrom_nonblock
may raise any error corresponding to recvfrom(2) failure, including Errno::EWOULDBLOCK.
If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitReadable
. So IO::WaitReadable
can be used to rescue the exceptions for retrying recvfrom_nonblock.
By specifying a keyword argument exception to false
, you can indicate that recvfrom_nonblock
should not raise an IO::WaitReadable
exception, but return the symbol :wait_readable
instead.