Erlang - Atoms

An atom is a literal, a constant with name. An atom is to be enclosed in single quotes (') if it does not begin with a lower-case letter or if it contains other characters than alphanumeric characters, underscore (_), or @.
The following program is an example of how atoms can be used in Erlang. This program declares 3 atoms, atom1, atom_1 and ‘atom 1’ respectively. So you can see the different ways an atom can be declared.

Example

-module(helloworld). 
-export([start/0]). 

start() -> 
   io:fwrite(atom1), 
   io:fwrite("~n"), 
   io:fwrite(atom_1), 
   io:fwrite("~n"), 
   io:fwrite('atom 1'), 
   io:fwrite("~n").

The output of the above program would be follows −

Output

atom1

atom_1

atom 1

Let’s see some of the methods available in Erlang to work with atoms.

S.No	Methods and Description
1	is_atom This method is used to determine if a term is indeed an atom.
2	atom_to_list This method is used to convert an atom to a list.
3	list_to_atom This method is used to convert a list item to an atom.
4	atom_to_binary This method is used to convert an atom to a binary value.
5	binary_to_atom This method is used to convert a binary value to an atom value.