About

Ranges represent a sequence of one or many consecutive integers. They:

Are created using the .. operator and can be both ascending or descending.
Their default step is 1, but can be modified using the ..// operator (since Elixir 1.12).
Are inclusive of the first and last values.
Implement the Enumerable protocol.
Are represented internally as a struct, but can be pattern matched using ...
Can be used with integers written in the binary, octal, hexadecimal, and code point notation.
Can be turned into lists with functions such as Enum.to_list/1 or Enum.map/2.

Enum.to_list(9..1)
# => [9, 8, 7, 6, 5, 4, 3, 2, 1]

Enum.map(?A..?F, &<<&1>>)
["A", "B", "C", "D", "E", "F"]