Operators

Operators work on values. For example, + adds two numbers:

local result = 2 + 2
lh.drawln(result) -- Output: 4

Assignment

= assigns a value. == compares two values:

local fps = 120
lh.drawln(fps == 120) -- Output: true

Concatenation

.. joins text. Numbers can also be joined to strings:

local fps = 120
lh.drawln("FPS: " .. fps) -- Output: FPS: 120

For other types, use tostring(value) first:

local enabled = true
lh.drawln("Enabled: " .. tostring(enabled)) -- Output: Enabled: true

Length

# gives a string’s length in bytes, or the length of a list without gaps:

lh.drawln(#"iFair") -- Output: 5
lh.drawln(#{ "FPS", "Position" }) -- Output: 2

Some characters use multiple bytes, so string length is not always the number of visible characters. For tables, # does not count named keys. See Tables.

Arithmetic operators

Operator	Description	Example	Result
+	Addition	10 + 4	14
-	Subtraction	10 - 4	6
*	Multiplication	10 * 4	40
/	Division	10 / 4	2.5
%	Modulo (remainder here)	10 % 4	2
^	Exponentiation	10 ^ 4	10000
-	Negation	-10	-10

Use parentheses when the order matters:

lh.drawln(2 + 3 * 4) -- Output: 14
lh.drawln((2 + 3) * 4) -- Output: 20

Comparison operators

These return true or false and are useful in conditionals.

Operator	Description	Example	Result
==	Equal	5 == 5	true
~=	Not equal	5 ~= 5	false
<	Less than	5 < 10	true
>	Greater than	5 > 10	false
<=	Less than or equal	5 <= 5	true
>=	Greater than or equal	5 >= 6	false

5 == "5" is false: a number and a string are different types. Convert numeric text with tonumber() before comparing it to a number.

Logical operators

Only false and nil are falsy. Everything else is truthy, including 0 and "".

Expression	Result
first and second	first if it is falsy; otherwise second
first or second	first if it is truthy; otherwise second
not value	true if value is falsy; otherwise false

and and or return one of their values, which is not necessarily a boolean. They only evaluate the second expression when needed. This is called short-circuiting.

local nickname = nil
local name = nickname or "Player"
lh.drawln(name) -- Output: Player

local fps = 120
lh.drawln(fps >= 60 and fps < 200) -- Output: true

or also replaces false, so use an explicit nil check if false is a value you want to keep. When combining logical operators, not runs before and, and and before or. Parentheses can make your intent clearer.