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Operators

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Lua provides a variety of different built-in operators.

Arithmetic operators

Those are operators to do usual math:

a = 20
b = 5

print(a + b) -- Addition operator. Prints 25

print(a - b) -- Substraction operator. Prints 15

print(a * b) -- Multiplication operator. Prints 100

print(a / b) -- Division operator. Prints 4.0

print(a ^ b) -- Exponent operator. Prints 3200000.0

print(a % b) -- Modulus operator. Prints 0

Comparative operators

Those operators are usually used to define some sort of condition. They produce boolean values.

a = 20
b = 5

print(a == b) -- Checks if a equals to b. Prints false

print(a ~= b) -- Checks if a is not equal to b. Prints true

print(a > b) -- Checks if a is greater than b. Prints true

print(a >= b) -- Checks if a is greater or equal to b. Prints true

print(a < b) -- Checks if a is less than b. Prints false

print(a <= b) -- Checks if a is less or equal to b. Prints false

Logical operators

Logic operators are used to compose complex conditions. They operate on boolean values and produces also boolean values.

a = 20
b = 5
c = 10
d = 30

print(a < b and c < d) -- Logical "and" operator. Prints false

print(a < b or c < d) -- Logical "or" operator. Prints true

print(not a < b) -- Logical negation operator. Prints true

Other operators

a = 20
t = {1, 2, 3}

s1 = "Hello, "
s2 = "World!"

print(-a) -- Unary minus operator. Prints -20

print(#t) -- Table size operator. Prints 3

print(s1 .. s2) -- String concatenation operator. Prints Hello, World!
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Learning plan

The most simple Lua program and where you can run it
A very brief overview of Lua syntax and expressions
A list of data types and their descriptions which Lua operates on
5. Operators
A list of built-in operators in Lua
A list of Lua statements which you use to organize control flow of a program
What kind of functions are there and how to write them
How to write tail recursion in Lua properly