How to convert a double to hex?

Hello, How do I convert a ruby float/double to high endian order hex with high bytes and low bytes.

EXAMPLE:

start with 99.0

end up with

40 58 C0 00   00 00 00 00
high bytes    low bytes

From stackoverflow

• The array class has a pack method:

  a = [99.0]
  s = a.pack("d")
  s
  => "\000\000\000\000\000\300X@"
  

  This gives you a byte string, but converting from that to hex for printing should be trivial.

  If you want to go the other way, the string class has an unpack method:

  s.unpack("d")
  =>[99.0]
  

• Well, like Patrick said, it doesn't take a lot to convert past using Array\#pack.

  irb> [99.0].pack('G').split('').map { |ds| ds[0] }
  #=> [64, 88, 192, 0, 0, 0, 0, 0]
  irb> _.map { |d| "%02x" % d }
  #=> ["40", "58", "c0", "00", "00", "00", "00", "00"]
  irb> [99.0].pack('E').split('').map { |ds| ds[0] }
  #=> [0, 0, 0, 0, 0, 192, 88, 64]
  irb> _.map { |d| "%02x" % d }    
  #=> ["00", "00", "00", "00", "00", "c0", "58", "40"]
  

  So it depends whether you want to unpack it with the high-order byte in the zero index or the low order byte in the zero index:

        E     |  Double-precision float, little-endian byte order
        G     |  Double-precision float, network (big-endian) byte order