Unpacking Strings Into Binary

You can find the binary representation of a given string by decoding it. Ruby comes equipped with the #unpack method on the String class that can do this decoding.

Though there are a variety of formats to decode a string into, here are some example of decoding different characters into binary.

> "A".unpack("B*")
=> ["01000001"]

The B* says unpack this into as many Binary digits as are needed. The UTF-8 encoding, means only a single byte (8-bits) are needed to represent "A".

irb(main):002:0> "Æ".unpack("B*")
=> ["1100001110000110"]
irb(main):003:0> "Æ".unpack("B8 B8")
=> ["11000011", "10000110"]

"Æ" is represented by two bytes. We can unpack each byte seprarately using "B8 B8".

irb(main):004:0> "木".unpack("B*")
=> ["111001101001110010101000"]
irb(main):005:0> "木".unpack("B8 B8 B8")
=> ["11100110", "10011100", "10101000"]

Similarly, this Japanese character is represented by three bytes of data.

irb(main):006:0> "👻".unpack("B*")
=> ["11110000100111111001000110111011"]
irb(main):007:0> "👻".unpack("B8 B8 B8 B8")
=> ["11110000", "10011111", "10010001", "10111011"]

Lastly, emojis generally require four bytes of data.

source