Number

Overview

The number type represents real (double-precision floating-point) numbers. Lua has no integer type, as it does not need it. There is a widespread misconception about floating-point arithmetic errors and some people fear that even a simple increment can go weird with floating-point numbers. The fact is that, when you use a double to represent an integer, there is no rounding error at all (unless the number is greater than 100,000,000,000,000). Specifically, a Lua number can represent any long integer without rounding problems. Moreover, most modern CPUs do floating-point arithmetic as fast as (or even faster than) integer arithmetic.

We can write numeric constants with an optional decimal part, plus an optional decimal exponent. Examples of valid numeric constants are:

4     0.4     4.57e-3     0.3e12     5e+20

local n1 = 10
local n2 = 5.12
local n3 = 3.14e-1

Content in this page is cited from the Lua 5.1 Reference Manual, freely available under the terms of the Lua license.