With no argument, returns the value of $~, which is the result of the most recent pattern match (see Regexp global variables):
/c(.)t/ =~ 'cat' # => 0 Regexp.last_match # => #<MatchData "cat" 1:"a"> /a/ =~ 'foo' # => nil Regexp.last_match # => nil
With non-negative integer argument n, returns the _n_th field in the matchdata, if any, or nil if none:
/c(.)t/ =~ 'cat' # => 0 Regexp.last_match(0) # => "cat" Regexp.last_match(1) # => "a" Regexp.last_match(2) # => nil
With negative integer argument n, counts backwards from the last field:
Regexp.last_match(-1) # => "a"
With string or symbol argument name, returns the string value for the named capture, if any:
/(?<lhs>\w+)\s*=\s*(?<rhs>\w+)/ =~ 'var = val' Regexp.last_match # => #<MatchData "var = val" lhs:"var"rhs:"val"> Regexp.last_match(:lhs) # => "var" Regexp.last_match('rhs') # => "val" Regexp.last_match('foo') # Raises IndexError.
Returns object if it is a regexp:
Regexp.try_convert(/re/) # => /re/
Otherwise if object responds to :to_regexp, calls object.to_regexp and returns the result.
Returns nil if object does not respond to :to_regexp.
Regexp.try_convert('re') # => nil
Raises an exception unless object.to_regexp returns a regexp.
Returns true if matching against re can be done in linear time to the input string.
Regexp.linear_time?(/re/) # => true
Note that this is a property of the ruby interpreter, not of the argument regular expression. Identical regexp can or cannot run in linear time depending on your ruby binary. Neither forward nor backward compatibility is guaranteed about the return value of this method. Our current algorithm is (*1) but this is subject to change in the future. Alternative implementations can also behave differently. They might always return false for everything.
Returns true if the class was initialized with keyword_init: true. Otherwise returns nil or false.
Examples:
Foo = Struct.new(:a) Foo.keyword_init? # => nil Bar = Struct.new(:a, keyword_init: true) Bar.keyword_init? # => true Baz = Struct.new(:a, keyword_init: false) Baz.keyword_init? # => false
Equivalent to self.to_s.start_with?; see String#start_with?.
Attempts to enter exclusive section. Returns false if lock fails.
Iterates over each line in the file and yields a String object for each.
Iterates over the entries (files and subdirectories) in the directory, yielding a Pathname object for each entry.
Packs port and host as an AF_INET/AF_INET6 sockaddr string.
Socket.sockaddr_in(80, "127.0.0.1") #=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00" Socket.sockaddr_in(80, "::1") #=> "\n\x00\x00P\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00"
Disallows further write using shutdown system call.
UNIXSocket.pair {|s1, s2| s1.print "ping" s1.close_write p s2.read #=> "ping" s2.print "pong" s2.close p s1.read #=> "pong" }
creates a new Socket connected to the address of local_addrinfo.
If local_addrinfo is nil, the address of the socket is not bound.
The timeout specify the seconds for timeout. Errno::ETIMEDOUT is raised when timeout occur.
If a block is given the created socket is yielded for each address.
returns a string which shows the sockaddr in addrinfo with human-readable form.
Addrinfo.tcp("localhost", 80).inspect_sockaddr #=> "127.0.0.1:80" Addrinfo.tcp("ip6-localhost", 80).inspect_sockaddr #=> "[::1]:80" Addrinfo.unix("/tmp/sock").inspect_sockaddr #=> "/tmp/sock"
Returns true for IPv4 private address (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16). It returns false otherwise.
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.
Returns true for IPv6 link local address (fe80::/10). It returns false otherwise.
Closes self for writing; closed-read setting remains unchanged.
Raises IOError if writing is attempted.
Related: StringIO#close, StringIO#close_read.