Data Types

Lua, like Python and Ruby, is a dynamically typed language, which means the data type does not have to be explicitly declared with the variable.

Data Classes

Lua has eight basic data types, which include: boolean, function, nil, number, string, table, thread, userdata. Some of the most commonly used are demonstrated below.

-- A boolean
flag = false
-- A string, strings can be declared with single or double quotes
name = "John Doe"
-- A number, in Lua there is not an integer type
num = 13
-- A function
function foo () return "bar" end

type()

Lua has a built-in type() function to retrieve the data type.

location = 'Maple Road'
print(type(location)) -- This outputs "string"

print(type(12/3)) -- This outputs "number"

Type Conversion

In Lua, type coercion automatically happens when strings and numbers are concatenated or when a string with a numeric value appears in an arithmetic expression.

--  The first type coercion is used in a concatenation to change a number to a string.

temperature = 56

print('Today’s temperature is ' .. temperature .. ' degrees.') -- This prints “Today’s temperature is 56 degrees.”

-- The second type of coercion is used during arithmetic expressions.
print('53' + 7)

-- This outputs 60 because it converted “53” to a number for the arithmetic.

Types can be manually converted by using the tostring() function to convert any data type to a string type:

player1Pts = 55

print('Player 1 has ' .. tostring(player1Pts) .. ' points')
-- This prints “Player 1 has 55 points”

The tonumber() function is used to convert any data type to a number type:

totalGuests = '30'

print(tonumber(totalGuests) / 5)
-- This prints 6