How to implement a smooth change of a variable (float)?

Question

Lua

Since there is such a function in my main language, but not in Lua - and the search result did not give anything, I turn to knowledgeable people here. I have no idea how to implement it.

UPD: Smooth change should be completed within a certain time interval

Answer 1

Divide the amount of smooth change by dividing the time interval. Check the time and change the value. It is hardly fashionable to attribute this to Lua as a language