The iterator version of the strongly_connected_components method. obj.each_strongly_connected_component is similar to obj.strongly_connected_components.each, but modification of obj during the iteration may lead to unexpected results.
each_strongly_connected_component returns nil.
class G include TSort def initialize(g) @g = g end def tsort_each_child(n, &b) @g[n].each(&b) end def tsort_each_node(&b) @g.each_key(&b) end end graph = G.new({1=>[2, 3], 2=>[4], 3=>[2, 4], 4=>[]}) graph.each_strongly_connected_component {|scc| p scc } #=> [4] # [2] # [3] # [1] graph = G.new({1=>[2], 2=>[3, 4], 3=>[2], 4=>[]}) graph.each_strongly_connected_component {|scc| p scc } #=> [4] # [2, 3] # [1]
The iterator version of the TSort.strongly_connected_components method.
The graph is represented by each_node and each_child. each_node should have call method which yields for each node in the graph. each_child should have call method which takes a node argument and yields for each child node.
g = {1=>[2, 3], 2=>[4], 3=>[2, 4], 4=>[]} each_node = lambda {|&b| g.each_key(&b) } each_child = lambda {|n, &b| g[n].each(&b) } TSort.each_strongly_connected_component(each_node, each_child) {|scc| p scc } #=> [4] # [2] # [3] # [1] g = {1=>[2], 2=>[3, 4], 3=>[2], 4=>[]} each_node = lambda {|&b| g.each_key(&b) } each_child = lambda {|n, &b| g[n].each(&b) } TSort.each_strongly_connected_component(each_node, each_child) {|scc| p scc } #=> [4] # [2, 3] # [1]
Tries to convert obj into an array, using to_ary method. Returns the converted array or nil if obj cannot be converted for any reason. This method can be used to check if an argument is an array.
Array.try_convert([1]) #=> [1] Array.try_convert("1") #=> nil if tmp = Array.try_convert(arg) # the argument is an array elsif tmp = String.try_convert(arg) # the argument is a string end
Returns the factorization of self.
See Prime#prime_division for more details.
Try to convert obj into a String, using to_str method. Returns converted string or nil if obj cannot be converted for any reason.
String.try_convert("str") #=> "str" String.try_convert(/re/) #=> nil
Converts a pathname to an absolute pathname. Relative paths are referenced from the current working directory of the process unless dir_string is given, in which case it will be used as the starting point. The given pathname may start with a “~”, which expands to the process owner’s home directory (the environment variable HOME must be set correctly). “~user” expands to the named user’s home directory.
File.expand_path("~oracle/bin") #=> "/home/oracle/bin"
A simple example of using dir_string is as follows.
File.expand_path("ruby", "/usr/bin") #=> "/usr/bin/ruby"
A more complex example which also resolves parent directory is as follows. Suppose we are in bin/mygem and want the absolute path of lib/mygem.rb.
File.expand_path("../../lib/mygem.rb", __FILE__) #=> ".../path/to/project/lib/mygem.rb"
So first it resolves the parent of __FILE__, that is bin/, then go to the parent, the root of the project and appends lib/mygem.rb.
Duplicates self and resets its day of calendar reform.
d = Date.new(1582,10,15) d.new_start(Date::JULIAN) #=> #<Date: 1582-10-05 ...>
Returns a Time object which denotes self.
Returns a DateTime object which denotes self.
Returns a Time object which denotes self.
Returns self.
Returns self.
Returns a DateTime object which denotes self.
Waits until IO is writable without blocking and returns self or nil when times out.
Try to convert obj into an IO, using to_io method. Returns converted IO or nil if obj cannot be converted for any reason.
IO.try_convert(STDOUT) #=> STDOUT IO.try_convert("STDOUT") #=> nil require 'zlib' f = open("/tmp/zz.gz") #=> #<File:/tmp/zz.gz> z = Zlib::GzipReader.open(f) #=> #<Zlib::GzipReader:0x81d8744> IO.try_convert(z) #=> #<File:/tmp/zz.gz>
Writes the given string to ios using the write(2) system call after O_NONBLOCK is set for the underlying file descriptor.
It returns the number of bytes written.
write_nonblock just calls the write(2) system call. It causes all errors the write(2) system call causes: Errno::EWOULDBLOCK, Errno::EINTR, etc. The result may also be smaller than string.length (partial write). The caller should care such errors and partial write.
If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitWritable. So IO::WaitWritable can be used to rescue the exceptions for retrying write_nonblock.
# Creates a pipe. r, w = IO.pipe # write_nonblock writes only 65536 bytes and return 65536. # (The pipe size is 65536 bytes on this environment.) s = "a" * 100000 p w.write_nonblock(s) #=> 65536 # write_nonblock cannot write a byte and raise EWOULDBLOCK (EAGAIN). p w.write_nonblock("b") # Resource temporarily unavailable (Errno::EAGAIN)
If the write buffer is not empty, it is flushed at first.
When write_nonblock raises an exception kind of IO::WaitWritable, write_nonblock should not be called until io is writable for avoiding busy loop. This can be done as follows.
begin result = io.write_nonblock(string) rescue IO::WaitWritable, Errno::EINTR IO.select(nil, [io]) retry end
Note that this doesn’t guarantee to write all data in string. The length written is reported as result and it should be checked later.
On some platforms such as Windows, write_nonblock is not supported according to the kind of the IO object. In such cases, write_nonblock raises Errno::EBADF.
By specifying a keyword argument exception to false, you can indicate that write_nonblock should not raise an IO::WaitWritable exception, but return the symbol :wait_writable instead.
Try to convert obj into a Regexp, using to_regexp method. Returns converted regexp or nil if obj cannot be converted for any reason.
Regexp.try_convert(/re/) #=> /re/ Regexp.try_convert("re") #=> nil o = Object.new Regexp.try_convert(o) #=> nil def o.to_regexp() /foo/ end Regexp.try_convert(o) #=> /foo/
Requests a connection to be made on the given remote_sockaddr after O_NONBLOCK is set for the underlying file descriptor. 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.sockaddr_in(80, 'www.google.com') begin # emulate blocking connect socket.connect_nonblock(sockaddr) rescue IO::WaitWritable IO.select(nil, [socket]) # wait 3-way handshake completion begin socket.connect_nonblock(sockaddr) # check connection failure rescue Errno::EISCONN end end socket.write("GET / HTTP/1.0\r\n\r\n") results = socket.read
Refer to Socket#connect for the exceptions that may be thrown if the call to connect_nonblock fails.
Socket#connect_nonblock may raise any error corresponding to connect(2) failure, including Errno::EINPROGRESS.
If the exception is Errno::EINPROGRESS, it is extended by IO::WaitWritable. So IO::WaitWritable can be used to rescue the exceptions for retrying connect_nonblock.
By specifying a keyword argument exception to false, you can indicate that connect_nonblock should not raise an IO::WaitWritable exception, but return the symbol :wait_writable instead.
# Socket#connect
Returns true for IPv4 multicast address (224.0.0.0/4). It returns false otherwise.
Returns true for IPv6 multicast address (ff00::/8). It returns false otherwise.