Add Unpacking Strings Into Binary as a ruby til

Author: jbranchaud

README.md

@@ -9,7 +9,7 @@ and pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://tinyletter.com/jbranchaud).
 
-_899 TILs and counting..._
+_900 TILs and counting..._
 
 ---
 
@@ -744,6 +744,7 @@ _899 TILs and counting..._
 - [Turning Things Into Hashes](ruby/turning-things-into-hashes.md)
 - [Uncaught Exceptions In Pry](ruby/uncaught-exceptions-in-pry.md)
 - [`undef_method` And The Inheritance Hierarchy](ruby/undef-method-and-the-inheritance-hierarchy.md)
+- [Unpacking Strings Into Binary](ruby/unpacking-strings-into-binary.md)
 - [Up And Down With Integers](ruby/up-and-down-with-integers.md)
 - [Use A Case Statement As A Cond Statement](ruby/use-a-case-statement-as-a-cond-statement.md)
 - [Use dotenv In A Non-Rails Project](ruby/use-dotenv-in-a-non-rails-project.md)

ruby/unpacking-strings-into-binary.md

@@ -0,0 +1,47 @@
+# Unpacking Strings Into Binary
+
+You can find the binary representation of a given string by decoding it. Ruby
+comes equipped with the [`#unpack`](https://apidock.com/ruby/String/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.
+
+```ruby
+> "A".unpack("B*")
+=> ["01000001"]
+```
+
+The `B*` says _unpack_ this into as many *B*inary digits as are needed. The
+UTF-8 encoding, means only a single byte (8-bits) are needed to represent
+`"A"`.
+
+```ruby
+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"`.
+
+```ruby
+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.
+
+```ruby
+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](https://www.honeybadger.io/blog/the-rubyist-guide-to-unicode-utf8/)