Returns self truncated (toward zero) to a precision of ndigits decimal digits.
When ndigits is negative, the returned value has at least ndigits.abs trailing zeros:
555.truncate(-1) # => 550 555.truncate(-2) # => 500 -555.truncate(-2) # => -500
Returns self when ndigits is zero or positive.
555.truncate # => 555 555.truncate(50) # => 555
Related: Integer#round.
Returns self truncated (toward zero) to a precision of digits decimal digits.
Numeric implements this by converting self to a Float and invoking Float#truncate.
Concatenates each object in objects to self and returns self:
s = 'foo' s.concat('bar', 'baz') # => "foobarbaz" s # => "foobarbaz"
For each given object object that is an Integer, the value is considered a codepoint and converted to a character before concatenation:
s = 'foo' s.concat(32, 'bar', 32, 'baz') # => "foo bar baz"
Related: String#<<, which takes a single argument.
Returns self truncated (toward zero) to a precision of ndigits decimal digits.
When ndigits is positive, returns a float with ndigits digits after the decimal point (as available):
f = 12345.6789 f.truncate(1) # => 12345.6 f.truncate(3) # => 12345.678 f = -12345.6789 f.truncate(1) # => -12345.6 f.truncate(3) # => -12345.678
When ndigits is negative, returns an integer with at least ndigits.abs trailing zeros:
f = 12345.6789 f.truncate(0) # => 12345 f.truncate(-3) # => 12000 f = -12345.6789 f.truncate(0) # => -12345 f.truncate(-3) # => -12000
Note that the limited precision of floating-point arithmetic may lead to surprising results:
(0.3 / 0.1).truncate #=> 2 (!)
Related: Float#round.
Returns the change time for the named file (the time at which directory information about the file was changed, not the file itself).
file_name can be an IO object.
Note that on Windows (NTFS), returns creation time (birth time).
File.ctime("testfile") #=> Wed Apr 09 08:53:13 CDT 2003
Truncates the file file_name to be at most integer bytes long. Not available on all platforms.
f = File.new("out", "w") f.write("1234567890") #=> 10 f.close #=> nil File.truncate("out", 5) #=> 0 File.size("out") #=> 5
Returns the change time for file (that is, the time directory information about the file was changed, not the file itself).
Note that on Windows (NTFS), returns creation time (birth time).
File.new("testfile").ctime #=> Wed Apr 09 08:53:14 CDT 2003
Truncates file to at most integer bytes. The file must be opened for writing. Not available on all platforms.
f = File.new("out", "w") f.syswrite("1234567890") #=> 10 f.truncate(5) #=> 0 f.close() #=> nil File.size("out") #=> 5
Returns the number of decimal digits in self:
BigDecimal("0").precision # => 0 BigDecimal("1").precision # => 1 BigDecimal("1.1").precision # => 2 BigDecimal("3.1415").precision # => 5 BigDecimal("-1e20").precision # => 21 BigDecimal("1e-20").precision # => 20 BigDecimal("Infinity").precision # => 0 BigDecimal("-Infinity").precision # => 0 BigDecimal("NaN").precision # => 0
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
Returns a string in asctime(3) format (but without “n0” at the end). This method is equivalent to strftime(‘%c’).
See also asctime(3) or ctime(3).
Returns a string in asctime(3) format (but without “n0” at the end). This method is equivalent to strftime(‘%c’).
See also asctime(3) or ctime(3).
Returns a canonical string representation of time.
Time.now.asctime #=> "Wed Apr 9 08:56:03 2003" Time.now.ctime #=> "Wed Apr 9 08:56:03 2003"
Returns a canonical string representation of time.
Time.now.asctime #=> "Wed Apr 9 08:56:03 2003" Time.now.ctime #=> "Wed Apr 9 08:56:03 2003"
Returns the values in self as an array:
Customer = Struct.new(:name, :address, :zip) joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345) joe.to_a # => ["Joe Smith", "123 Maple, Anytown NC", 12345]
Struct#values and Struct#deconstruct are aliases for Struct#to_a.
Related: members.
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.
Returns the last change time, using directory information, not the file itself.
See File.ctime.
Requests a connection to be made on the given remote_sockaddr. Returns 0 if successful, otherwise an exception is raised.
remote_sockaddr - the struct sockaddr contained in a string or Addrinfo object
# Pull down Google's web page require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) sockaddr = Socket.pack_sockaddr_in( 80, 'www.google.com' ) socket.connect( sockaddr ) socket.write( "GET / HTTP/1.0\r\n\r\n" ) results = socket.read
On unix-based systems the following system exceptions may be raised if the call to connect fails:
Errno::EACCES - search permission is denied for a component of the prefix path or write access to the socket is denied
Errno::EADDRINUSE - the sockaddr is already in use
Errno::EADDRNOTAVAIL - the specified sockaddr is not available from the local machine
Errno::EAFNOSUPPORT - the specified sockaddr is not a valid address for the address family of the specified socket
Errno::EALREADY - a connection is already in progress for the specified socket
Errno::EBADF - the socket is not a valid file descriptor
Errno::ECONNREFUSED - the target sockaddr was not listening for connections refused the connection request
Errno::ECONNRESET - the remote host reset the connection request
Errno::EFAULT - the sockaddr cannot be accessed
Errno::EHOSTUNREACH - the destination host cannot be reached (probably because the host is down or a remote router cannot reach it)
Errno::EINPROGRESS - the O_NONBLOCK is set for the socket and the connection cannot be immediately established; the connection will be established asynchronously
Errno::EINTR - the attempt to establish the connection was interrupted by delivery of a signal that was caught; the connection will be established asynchronously
Errno::EISCONN - the specified socket is already connected
Errno::EINVAL - the address length used for the sockaddr is not a valid length for the address family or there is an invalid family in sockaddr
Errno::ENAMETOOLONG - the pathname resolved had a length which exceeded PATH_MAX
Errno::ENETDOWN - the local interface used to reach the destination is down
Errno::ENETUNREACH - no route to the network is present
Errno::ENOBUFS - no buffer space is available
Errno::ENOSR - there were insufficient STREAMS resources available to complete the operation
Errno::ENOTSOCK - the socket argument does not refer to a socket
Errno::EOPNOTSUPP - the calling socket is listening and cannot be connected
Errno::EPROTOTYPE - the sockaddr has a different type than the socket bound to the specified peer address
Errno::ETIMEDOUT - the attempt to connect timed out before a connection was made.
On unix-based systems if the address family of the calling socket is AF_UNIX the follow exceptions may be raised if the call to connect fails:
Errno::EIO - an i/o error occurred while reading from or writing to the file system
Errno::ELOOP - too many symbolic links were encountered in translating the pathname in sockaddr
Errno::ENAMETOOLLONG - a component of a pathname exceeded NAME_MAX characters, or an entire pathname exceeded PATH_MAX characters
Errno::ENOENT - a component of the pathname does not name an existing file or the pathname is an empty string
Errno::ENOTDIR - a component of the path prefix of the pathname in sockaddr is not a directory
On Windows systems the following system exceptions may be raised if the call to connect fails:
Errno::ENETDOWN - the network is down
Errno::EADDRINUSE - the socket’s local address is already in use
Errno::EINTR - the socket was cancelled
Errno::EINPROGRESS - a blocking socket is in progress or the service provider is still processing a callback function. Or a nonblocking connect call is in progress on the socket.
Errno::EALREADY - see Errno::EINVAL
Errno::EADDRNOTAVAIL - the remote address is not a valid address, such as ADDR_ANY TODO check ADDRANY TO INADDR_ANY
Errno::EAFNOSUPPORT - addresses in the specified family cannot be used with with this socket
Errno::ECONNREFUSED - the target sockaddr was not listening for connections refused the connection request
Errno::EFAULT - the socket’s internal address or address length parameter is too small or is not a valid part of the user space address
Errno::EINVAL - the socket is a listening socket
Errno::EISCONN - the socket is already connected
Errno::ENETUNREACH - the network cannot be reached from this host at this time
Errno::EHOSTUNREACH - no route to the network is present
Errno::ENOBUFS - no buffer space is available
Errno::ENOTSOCK - the socket argument does not refer to a socket
Errno::ETIMEDOUT - the attempt to connect timed out before a connection was made.
Errno::EWOULDBLOCK - the socket is marked as nonblocking and the connection cannot be completed immediately
Errno::EACCES - the attempt to connect the datagram socket to the broadcast address failed
connect manual pages on unix-based systems
connect function in Microsoft’s Winsock functions reference
creates a socket connected to the address of self.
The optional argument opts is options represented by a hash. opts may have following options:
specify the timeout in seconds.
If a block is given, it is called with the socket and the value of the block is returned. The socket is returned otherwise.
Addrinfo.tcp("www.ruby-lang.org", 80).connect {|s| s.print "GET / HTTP/1.0\r\nHost: www.ruby-lang.org\r\n\r\n" puts s.read }
Connects udpsocket to host:port.
This makes possible to send without destination address.
u1 = UDPSocket.new u1.bind("127.0.0.1", 4913) u2 = UDPSocket.new u2.connect("127.0.0.1", 4913) u2.send "uuuu", 0 p u1.recvfrom(10) #=> ["uuuu", ["AF_INET", 33230, "localhost", "127.0.0.1"]]
Truncates the buffer string to at most integer bytes. The stream must be opened for writing.