Arrays, lists and strings

In September 1992, according to Rob Pike, Ken Thompson sketched a new way to store Unicode text on a placemat in a New Jersey diner. Within days their Plan 9 operating system at Bell Labs was running on it.

The scheme was UTF-8. It stores the 128 ASCII characters in one byte each, exactly as before, and everything else in two to four bytes. Today it is the default encoding of the web and of Python source code. It is also why len("café") and the number of bytes that word occupies on disk are different numbers.