Returns an Array of two Integer values.
The first value is the current number of significant digits in the BigDecimal. The second value is the maximum number of significant digits for the BigDecimal.
BigDecimal('5').precs #=> [9, 18]
Round to the nearest integer (by default), returning the result as a BigDecimal.
BigDecimal('3.14159').round #=> 3 BigDecimal('8.7').round #=> 9 BigDecimal('-9.9').round #=> -10
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').round(3) #=> 3.142 BigDecimal('13345.234').round(-2) #=> 13300.0
The value of the optional mode argument can be used to determine how rounding is performed; see BigDecimal.mode.
Returns True if the value is zero.
Returns self if the value is non-zero, nil otherwise.
Returns rat rounded to the nearest value 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).round #=> 3 Rational(2, 3).round #=> 1 Rational(-3, 2).round #=> -2 # decimal - 1 2 3 . 4 5 6 # ^ ^ ^ ^ ^ ^ # precision -3 -2 -1 0 +1 +2 Rational('-123.456').round(+1).to_f #=> -123.5 Rational('-123.456').round(-1) #=> -120
The optional half keyword argument is available similar to Float#round.
Rational(25, 100).round(1, half: :up) #=> (3/10) Rational(25, 100).round(1, half: :down) #=> (1/5) Rational(25, 100).round(1, half: :even) #=> (1/5) Rational(35, 100).round(1, half: :up) #=> (2/5) Rational(35, 100).round(1, half: :down) #=> (3/10) Rational(35, 100).round(1, half: :even) #=> (2/5) Rational(-25, 100).round(1, half: :up) #=> (-3/10) Rational(-25, 100).round(1, half: :down) #=> (-1/5) Rational(-25, 100).round(1, half: :even) #=> (-1/5)
Same as Time::gm, but interprets the values in the local time zone.
Time.local(2000,"jan",1,20,15,1) #=> 2000-01-01 20:15:01 -0600
Converts time to local time (using the local time zone in effect at the creation time of time) modifying the receiver.
If utc_offset is given, it is used instead of the local time.
t = Time.utc(2000, "jan", 1, 20, 15, 1) #=> 2000-01-01 20:15:01 UTC t.utc? #=> true t.localtime #=> 2000-01-01 14:15:01 -0600 t.utc? #=> false t.localtime("+09:00") #=> 2000-01-02 05:15:01 +0900 t.utc? #=> false
If utc_offset is not given and time is local time, just returns the receiver.
Returns a new Time object representing time in local time (using the local time zone in effect for this process).
If utc_offset is given, it is used instead of the local time. utc_offset can be given as a human-readable string (eg. "+09:00") or as a number of seconds (eg. 32400).
t = Time.utc(2000,1,1,20,15,1) #=> 2000-01-01 20:15:01 UTC t.utc? #=> true l = t.getlocal #=> 2000-01-01 14:15:01 -0600 l.utc? #=> false t == l #=> true j = t.getlocal("+09:00") #=> 2000-01-02 05:15:01 +0900 j.utc? #=> false t == j #=> true k = t.getlocal(9*60*60) #=> 2000-01-02 05:15:01 +0900 k.utc? #=> false t == k #=> true
Rounds sub seconds to a given precision in decimal digits (0 digits by default). It returns a new Time object. ndigits should be zero or a positive integer.
require 'time' t = Time.utc(2010,3,30, 5,43,"25.123456789".to_r) t.iso8601(10) #=> "2010-03-30T05:43:25.1234567890Z" t.round.iso8601(10) #=> "2010-03-30T05:43:25.0000000000Z" t.round(0).iso8601(10) #=> "2010-03-30T05:43:25.0000000000Z" t.round(1).iso8601(10) #=> "2010-03-30T05:43:25.1000000000Z" t.round(2).iso8601(10) #=> "2010-03-30T05:43:25.1200000000Z" t.round(3).iso8601(10) #=> "2010-03-30T05:43:25.1230000000Z" t.round(4).iso8601(10) #=> "2010-03-30T05:43:25.1235000000Z" t.round(5).iso8601(10) #=> "2010-03-30T05:43:25.1234600000Z" t.round(6).iso8601(10) #=> "2010-03-30T05:43:25.1234570000Z" t.round(7).iso8601(10) #=> "2010-03-30T05:43:25.1234568000Z" t.round(8).iso8601(10) #=> "2010-03-30T05:43:25.1234567900Z" t.round(9).iso8601(10) #=> "2010-03-30T05:43:25.1234567890Z" t.round(10).iso8601(10) #=> "2010-03-30T05:43:25.1234567890Z" t = Time.utc(1999,12,31, 23,59,59) (t + 0.4).round.iso8601(3) #=> "1999-12-31T23:59:59.000Z" (t + 0.49).round.iso8601(3) #=> "1999-12-31T23:59:59.000Z" (t + 0.5).round.iso8601(3) #=> "2000-01-01T00:00:00.000Z" (t + 1.4).round.iso8601(3) #=> "2000-01-01T00:00:00.000Z" (t + 1.49).round.iso8601(3) #=> "2000-01-01T00:00:00.000Z" (t + 1.5).round.iso8601(3) #=> "2000-01-01T00:00:01.000Z" t = Time.utc(1999,12,31, 23,59,59) (t + 0.123456789).round(4).iso8601(6) #=> "1999-12-31T23:59:59.123500Z"
Returns true if an IO object is in non-blocking mode.
Enables non-blocking mode on a stream when set to true, and blocking mode when set to false.
Yields self in non-blocking mode.
When false is given as an argument, self is yielded in blocking mode. The original mode is restored after the block is executed.
Writes the given object(s) to ios. Returns nil.
The stream must be opened for writing. Each given object that isn’t a string will be converted by calling its to_s method. When called without arguments, prints the contents of $_.
If the output field separator ($,) is not nil, it is inserted between objects. If the output record separator ($\) is not nil, it is appended to the output.
$stdout.print("This is ", 100, " percent.\n")
produces:
This is 100 percent.
Formats and writes to ios, converting parameters under control of the format string. See Kernel#sprintf for details.
Reads maxlen bytes from ios using the pread system call and returns them as a string without modifying the underlying descriptor offset. This is advantageous compared to combining IO#seek and IO#read in that it is atomic, allowing multiple threads/process to share the same IO object for reading the file at various locations. This bypasses any userspace buffering of the IO layer. If the optional outbuf argument is present, it must reference a String, which will receive the data. Raises SystemCallError on error, EOFError at end of file and NotImplementedError if platform does not implement the system call.
File.write("testfile", "This is line one\nThis is line two\n") File.open("testfile") do |f| p f.read # => "This is line one\nThis is line two\n" p f.pread(12, 0) # => "This is line" p f.pread(9, 8) # => "line one\n" end
Provides a mechanism for issuing low-level commands to control or query I/O devices. Arguments and results are platform dependent. If arg is a number, its value is passed directly. If it is a string, it is interpreted as a binary sequence of bytes. On Unix platforms, see ioctl(2) for details. Not implemented on all platforms.
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
Predicate method for root directories. Returns true if the pathname consists of consecutive slashes.
It doesn’t access the filesystem. So it may return false for some pathnames which points to roots such as /usr/...
Return true if parsed source has errors.
Receives up to maxlen bytes from socket. 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.
maxlen - the maximum number of bytes to receive from the socket
flags - zero or more of the MSG_ options
# In one file, start this first require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' ) socket.bind( sockaddr ) socket.listen( 5 ) client, client_addrinfo = socket.accept data = client.recvfrom( 20 )[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.pack_sockaddr_in( 2200, 'localhost' ) socket.connect( sockaddr ) socket.puts "Watch this get cut short!" socket.close
On unix-based based systems the following system exceptions may be raised if the call to recvfrom fails:
Errno::EAGAIN - the socket file descriptor is marked as O_NONBLOCK and no data is waiting to be received; or MSG_OOB is set and no out-of-band data is available and either the socket file descriptor is marked as O_NONBLOCK or the socket does not support blocking to wait for out-of-band-data
Errno::EWOULDBLOCK - see Errno::EAGAIN
Errno::EBADF - the socket is not a valid file descriptor
Errno::ECONNRESET - a connection was forcibly closed by a peer
Errno::EFAULT - the socket’s internal buffer, address or address length cannot be accessed or written
Errno::EINTR - a signal interrupted recvfrom before any data was available
Errno::EINVAL - the MSG_OOB flag is set and no out-of-band data is available
Errno::EIO - an i/o error occurred while reading from or writing to the filesystem
Errno::ENOBUFS - insufficient resources were available in the system to perform the operation
Errno::ENOMEM - insufficient memory was available to fulfill the request
Errno::ENOSR - there were insufficient STREAMS resources available to complete the operation
Errno::ENOTCONN - a receive is attempted on a connection-mode socket that is not connected
Errno::ENOTSOCK - the socket does not refer to a socket
Errno::EOPNOTSUPP - the specified flags are not supported for this socket type
Errno::ETIMEDOUT - the connection timed out during connection establishment or due to a transmission timeout on an active connection
On Windows systems the following system exceptions may be raised if the call to recvfrom fails:
Errno::ENETDOWN - the network is down
Errno::EFAULT - the internal buffer and from parameters on socket are not part of the user address space, or the internal fromlen parameter is too small to accommodate the peer address
Errno::EINTR - the (blocking) call was cancelled by an internal call to the WinSock function WSACancelBlockingCall
Errno::EINPROGRESS - a blocking Windows Sockets 1.1 call is in progress or the service provider is still processing a callback function
Errno::EINVAL - socket has not been bound with a call to bind, or an unknown flag was specified, or MSG_OOB was specified for a socket with SO_OOBINLINE enabled, or (for byte stream-style sockets only) the internal len parameter on socket was zero or negative
Errno::EISCONN - socket is already connected. The call to recvfrom is not permitted with a connected socket on a socket that is connection oriented or connectionless.
Errno::ENETRESET - the connection has been broken due to the keep-alive activity detecting a failure while the operation was in progress.
Errno::EOPNOTSUPP - MSG_OOB was specified, but socket is not stream-style such as type SOCK_STREAM. OOB data is not supported in the communication domain associated with socket, or socket is unidirectional and supports only send operations
Errno::ESHUTDOWN - socket has been shutdown. It is not possible to call recvfrom on a socket after shutdown has been invoked.
Errno::EWOULDBLOCK - socket is marked as nonblocking and a call to recvfrom would block.
Errno::EMSGSIZE - the message was too large to fit into the specified buffer and was truncated.
Errno::ETIMEDOUT - the connection has been dropped, because of a network failure or because the system on the other end went down without notice
Errno::ECONNRESET - the virtual circuit was reset by the remote side executing a hard or abortive close. The application should close the socket; it is no longer usable. On a UDP-datagram socket this error indicates a previous send operation resulted in an ICMP Port Unreachable message.
Creates a pair of sockets connected each other.
domain should be a communications domain such as: :INET, :INET6, :UNIX, etc.
socktype should be a socket type such as: :STREAM, :DGRAM, :RAW, etc.
protocol should be a protocol defined in the domain, defaults to 0 for the domain.
s1, s2 = Socket.pair(:UNIX, :STREAM, 0) s1.send "a", 0 s1.send "b", 0 s1.close p s2.recv(10) #=> "ab" p s2.recv(10) #=> "" p s2.recv(10) #=> "" s1, s2 = Socket.pair(:UNIX, :DGRAM, 0) s1.send "a", 0 s1.send "b", 0 p s2.recv(10) #=> "a" p s2.recv(10) #=> "b"