Introduction to Lua Types

Lua is a dynamically typed language, which means that variables do not have types; only values do. There are no type definitions in the language. All values carry their own type.

In Lua, there are eight basic types:

• nil: represents the absence of a useful value
• boolean: has two values - false and true
• number: represents real (double-precision floating-point) numbers
• string: represents arrays of characters
• function: represents a first-class value with code
• userdata: represents arbitrary C data
• thread: represents independent threads of execution
• table: represents ordinary arrays, symbol tables, sets, records, graphs, trees, etc.

The function type returns a string describing the type of a given value:

print(type("Hello world"))  --> string
print(type(10.4))           --> number
print(type(true))           --> boolean
print(type(nil))            --> nil
print(type(type(10.4)))    --> string