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A recommended version for use with a ~> Requirement.

Calls the block with each repeated combination of length n of the elements of self; each combination is an Array; returns self. The order of the combinations is indeterminate.

When a block and a positive Integer argument n are given, calls the block with each n-tuple repeated combination of the elements of self. The number of combinations is (n+1)(n+2)/2.

n = 1:

a = [0, 1, 2]
a.repeated_combination(1) {|combination| p combination }

Output:

[0]
[1]
[2]

n = 2:

a.repeated_combination(2) {|combination| p combination }

Output:

[0, 0]
[0, 1]
[0, 2]
[1, 1]
[1, 2]
[2, 2]

If n is zero, calls the block once with an empty Array.

If n is negative, does not call the block:

a.repeated_combination(-1) {|combination| fail 'Cannot happen' }

Returns a new Enumerator if no block given:

a = [0, 1, 2]
a.repeated_combination(2) # => #<Enumerator: [0, 1, 2]:combination(2)>

Using Enumerators, it’s convenient to show the combinations and counts for some values of n:

e = a.repeated_combination(0)
e.size # => 1
e.to_a # => [[]]
e = a.repeated_combination(1)
e.size # => 3
e.to_a # => [[0], [1], [2]]
e = a.repeated_combination(2)
e.size # => 6
e.to_a # => [[0, 0], [0, 1], [0, 2], [1, 1], [1, 2], [2, 2]]

Makes a list of existing constants private.

Makes a list of existing constants deprecated. Attempt to refer to them will produce a warning.

module HTTP
  NotFound = Exception.new
  NOT_FOUND = NotFound # previous version of the library used this name

  deprecate_constant :NOT_FOUND
end

HTTP::NOT_FOUND
# warning: constant HTTP::NOT_FOUND is deprecated

Returns true if the given calendar date is valid, and false if not. Valid in this context is whether the arguments passed to this method would be accepted by ::new.

Date.valid_date?(2001,2,3)        #=> true
Date.valid_date?(2001,2,29)       #=> false
Date.valid_date?(2001,2,-1)       #=> true

See also ::jd and ::civil.

Returns self.

Returns a DateTime object which denotes self.

Returns a Date object which denotes self.

Returns self.

Returns a Date object which denotes self.

Returns a DateTime object which denotes self.

Returns true if this class can be used to create an instance from a serialised JSON string. The class has to implement a class method json_create that expects a hash as first parameter. The hash should include the required data.

Returns garbage collector generation for the given object.

class B
  include ObjectSpace

  def foo
    trace_object_allocations do
      obj = Object.new
      p "Generation is #{allocation_generation(obj)}"
    end
  end
end

B.new.foo #=> "Generation is 3"

See ::trace_object_allocations for more information and examples.

Takes a hash as its argument. The key is a symbol or an array of symbols. These symbols correspond to method names, instance variable names, or constant names (see def_delegator). The value is the accessor to which the methods will be delegated.

How String Gem paths should be split. Overridable for esoteric platforms.

Returns the status of the last executed child process in the current thread.

Process.wait Process.spawn("ruby", "-e", "exit 13")
Process.last_status   #=> #<Process::Status: pid 4825 exit 13>

If no child process has ever been executed in the current thread, this returns nil.

Process.last_status   #=> nil

Update the digest using given string and return self.

Update the digest using a given string and return self.

Encrypts data in a streaming fashion. Hand consecutive blocks of data to the update method in order to encrypt it. Returns the encrypted data chunk. When done, the output of Cipher#final should be additionally added to the result.

If buffer is given, the encryption/decryption result will be written to it. buffer will be resized automatically.

Not every message digest can be computed in one single pass. If a message digest is to be computed from several subsequent sources, then each may be passed individually to the Digest instance.

Example

digest = OpenSSL::Digest.new('SHA256')
digest.update('First input')
digest << 'Second input' # equivalent to digest.update('Second input')
result = digest.digest