method

random_number

ruby latest stable - Class: SecureRandom

random_number(n=0)

public

SecureRandom.random_number generates a random number.

If a positive integer is given as n, SecureRandom.random_number returns an integer: 0 <= SecureRandom.random_number(n) < n.

p SecureRandom.random_number(100) #=> 15
p SecureRandom.random_number(100) #=> 88

If 0 is given or an argument is not given, SecureRandom.random_number returns a float: 0.0 <= SecureRandom.random_number() < 1.0.

p SecureRandom.random_number #=> 0.596506046187744
p SecureRandom.random_number #=> 0.350621695741409

# File lib/securerandom.rb, line 246
  def self.random_number(n=0)
    if 0 < n
      if defined? OpenSSL::BN
        OpenSSL::BN.rand_range(n).to_i
      else
        hex = n.to_s(16)
        hex = '0' + hex if (hex.length & 1) == 1
        bin = [hex].pack("H*")
        mask = bin[0].ord
        mask |= mask >> 1
        mask |= mask >> 2
        mask |= mask >> 4
        begin
          rnd = SecureRandom.random_bytes(bin.length)
          rnd[0] = (rnd[0].ord & mask).chr
        end until rnd < bin
        rnd.unpack("H*")[0].hex
      end
    else
      # assumption: Float::MANT_DIG <= 64
      if defined? OpenSSL::BN
        i64 = OpenSSL::BN.rand(64, -1).to_i
      else
        i64 = SecureRandom.random_bytes(8).unpack("Q")[0]
      end
      Math.ldexp(i64 >> (64-Float::MANT_DIG), -Float::MANT_DIG)
    end
  end

random_number

Method deprecated or moved

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