String

"hello"
"string" <> "concat"

x = 123
x <> "hi" #error
"#{x}hi" #123hi

String.reverse(str)

String.upcase(str)

String.downcase(str)

String.capitalize(str)

String.starts_with?(str)

String.contains?(str, "search_str")

String.first(str)

String.at(str, index)

String.slice(str, start_index, end_index)

String.split("foo bar", "")

String.length("foo bar")

Atoms

An atom is a constant whose value is its own name

true, false, and nil are atoms, but can skip :

:apple
:ok != :error
:true == true
is_atom(false) # => true
true and true
false or not true
1 and true # => raises exception
Atom.to_string(:foo) 

Atoms are not garbage collected, so never convert user input to atoms