Creates a pair of sockets connected to each other.
socktype should be a socket type such as: :STREAM, :DGRAM, :RAW, etc.
protocol should be a protocol defined in the domain. 0 is default protocol for the domain.
s1, s2 = UNIXSocket.pair s1.send "a", 0 s1.send "b", 0 p s2.recv(10) #=> "ab"
Returns dispatch ID.
tobj = WIN32OLE_TYPE.new('Microsoft Excel 9.0 Object Library', 'Workbooks') method = WIN32OLE_METHOD.new(tobj, 'Add') puts method.dispid # => 181
Extracts the nested value specified by the sequence of key objects by calling dig at each step, returning nil if any intermediate step is nil.
h = { foo: {bar: {baz: 1}}} h.dig(:foo, :bar, :baz) #=> 1 h.dig(:foo, :zot, :xyz) #=> nil g = { foo: [10, 11, 12] } g.dig(:foo, 1) #=> 11 g.dig(:foo, 1, 0) #=> TypeError: Integer does not have #dig method g.dig(:foo, :bar) #=> TypeError: no implicit conversion of Symbol into Integer
Synonym for $stdin.
Opens an IRB session where binding.irb is called which allows for interactive debugging. You can call any methods or variables available in the current scope, and mutate state if you need to.
Given a Ruby file called potato.rb containing the following code:
class Potato def initialize @cooked = false binding.irb puts "Cooked potato: #{@cooked}" end end Potato.new
Running +ruby potato.rb+ will open an IRB session where binding.irb is called, and you will see the following:
$ ruby potato.rb
From: potato.rb @ line 4 :
1: class Potato
2: def initialize
3: @cooked = false
=> 4: binding.irb
5: puts "Cooked potato: #{@cooked}"
6: end
7: end
8:
9: Potato.new
irb(#<Potato:0x00007feea1916670>):001:0>
You can type any valid Ruby code and it will be evaluated in the current context. This allows you to debug without having to run your code repeatedly:
irb(#<Potato:0x00007feea1916670>):001:0> @cooked => false irb(#<Potato:0x00007feea1916670>):002:0> self.class => Potato irb(#<Potato:0x00007feea1916670>):003:0> caller.first => ".../2.5.1/lib/ruby/2.5.0/irb/workspace.rb:85:in `eval'" irb(#<Potato:0x00007feea1916670>):004:0> @cooked = true => true
You can exit the IRB session with the ‘exit` command. Note that exiting will resume execution where binding.irb had paused it, as you can see from the output printed to standard output in this example:
irb(#<Potato:0x00007feea1916670>):005:0> exit Cooked potato: true
See IRB for more information.
Creates a matrix where the diagonal elements are composed of values.
Matrix.diagonal(9, 5, -3)
=> 9 0 0
0 5 0
0 0 -3
Returns true if this is a diagonal matrix. Raises an error if matrix is not square.
Parses environment variable env or its uppercase with splitting like a shell.
env defaults to the basename of the program.
Returns true if the set and the given set have no element in common. This method is the opposite of intersect?.
Set[1, 2, 3].disjoint? Set[3, 4] #=> false Set[1, 2, 3].disjoint? Set[4, 5] #=> true
Divides the set into a set of subsets according to the commonality defined by the given block.
If the arity of the block is 2, elements o1 and o2 are in common if block.call(o1, o2) is true. Otherwise, elements o1 and o2 are in common if block.call(o1) == block.call(o2).
require 'set' numbers = Set[1, 3, 4, 6, 9, 10, 11] set = numbers.divide { |i,j| (i - j).abs == 1 } set #=> #<Set: {#<Set: {1}>, # #<Set: {11, 9, 10}>, # #<Set: {3, 4}>, # #<Set: {6}>}>
Returns an enumerator if no block is given.
Deactivates the trace
Return true if trace was enabled. Return false if trace was disabled.
trace.enabled? #=> true trace.disable #=> true (previous status) trace.enabled? #=> false trace.disable #=> false
If a block is given, the trace will only be disable within the scope of the block.
trace.enabled? #=> true trace.disable do trace.enabled? # only disabled for this block end trace.enabled? #=> true
Note: You cannot access event hooks within the block.
trace.disable { p tp.lineno } #=> RuntimeError: access from outside
Return the generated binding object from event
Returns the binding associated with prc.
def fred(param) proc {} end b = fred(99) eval("param", b.binding) #=> 99
When RubyGems is required, Kernel#require is replaced with our own which is capable of loading gems on demand.
When you call require 'x', this is what happens:
If the file can be loaded from the existing Ruby loadpath, it is.
Otherwise, installed gems are searched for a file that matches. If it’s found in gem ‘y’, that gem is activated (added to the loadpath).
The normal require functionality of returning false if that file has already been loaded is preserved.
Returns a Binding object, describing the variable and method bindings at the point of call. This object can be used when calling eval to execute the evaluated command in this environment. See also the description of class Binding.
def get_binding(param) binding end b = get_binding("hello") eval("param", b) #=> "hello"
Returns the first element, or the first n elements, of the enumerable. If the enumerable is empty, the first form returns nil, and the second form returns an empty array.
%w[foo bar baz].first #=> "foo" %w[foo bar baz].first(2) #=> ["foo", "bar"] %w[foo bar baz].first(10) #=> ["foo", "bar", "baz"] [].first #=> nil [].first(10) #=> []
Returns a Digest subclass by name
require 'openssl' OpenSSL::Digest("MD5") # => OpenSSL::Digest::MD5 Digest("Foo") # => NameError: wrong constant name Foo
Returns a Digest subclass by name
require 'openssl' OpenSSL::Digest("MD5") # => OpenSSL::Digest::MD5 Digest("Foo") # => NameError: wrong constant name Foo
Change what’s displayed on the screen to reflect the current contents.
See GNU Readline’s rl_redisplay function.
Raises NotImplementedError if the using readline library does not support.
Disables garbage collection, returning true if garbage collection was already disabled.
GC.disable #=> false GC.disable #=> true
Redirects to a path ending in /
Returns true if the entry is a directory (i.e., the value of the type fact is dir, cdir, or pdir).