Opeartors

An operator is a special set of symbols used to perform an operation or conditional evaluation.

Logical

The logical operators for conditional statements are and, or, and not. These operators consider both false and nil as “false” and anything else as “true.”

Operator	Description
and	Evaluates as true only if both conditions are true
or	Evaluates as true if either condition is true
not	Evaluates as the opposite of the condition

Relational

Relational operators compare two parameters and return a boolean true or false.

Operator	Description	Associated metamethod
==	Equal to	__eq
~=	Not equal to
>	Greater than
<	Less than	__lt
>=	Greater than or equal to
<=	Less than or equal to	__le

Arithmetic

Lua supports the usual binary operators along with exponentiation, modulus, and unary negation.

Operator	Description	Example	Associated metamethod
+	Addition	1 + 1 = 2	__add
-	Subtraction	1 - 1 = 0	__sub
*	Multiplication	5 * 5 = 25	__mul
/	Division	10 / 5 = 2	__div
^	Exponentiation	2 ^ 4 = 16	__pow
%	Modulus	13 % 7 = 6	__mod
-	Unary negation	-2 = 0 - 2	__unm

Miscellaneous

Miscellaneous operators include concatenation and length.

Operator	Description	Associated metamethod
..	Concatenates two strings	__concat
#	Length of table	__len

Compound Assignment

Compound assignment operators are used to set a variable equal to the result of an operation where the first parameter is the variable’s current value.

The expression on the left side of a compound assignment is only evaluated once. For example, if an expression generates a random index in a table, the same index is used for both the operation and the assignment.

Operator	Operation
+=	Addition
-=	Subtraction
*=	Multiplication
/=	Division
%=	Modulus
^=	Exponentiation
..=	Concatenation