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instance method

Random::Formatter#uuid

() -> ::String

uuid

lib/random/formatter.rb View on GitHub ↗

# File tmp/rubies/ruby-4.1.0-preview1/lib/random/formatter.rb, line 169
def uuid
  ary = random_bytes(16)
  ary.setbyte(6, (ary.getbyte(6) & 0x0f) | 0x40)
  ary.setbyte(8, (ary.getbyte(8) & 0x3f) | 0x80)
  ary.unpack("H8H4H4H4H12").join(?-)
end

Generate a random v4 UUID (Universally Unique IDentifier).

Example

require 'random/formatter'

Random.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
Random.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"
# or
prng = Random.new
prng.uuid #=> "62936e70-1815-439b-bf89-8492855a7e6b"

The version 4 UUID is purely random (except the version). It doesn’t contain meaningful information such as MAC addresses, timestamps, etc.

The result contains 122 random bits (15.25 random bytes).

See RFC9562 for details of UUIDv4.

See also #urlsafe_base64 #uuid_v4 #random_number #uuid_v7 also in 4.0 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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