Being a number

Questions
1

Hi!
Is it any code that says “if x== a number then text(x/2)” and “if x~= a number then text(x)”? I’m looking for a code that’s check if it is a number or just a word

2

if type(x)=="number"

3

Thanks @yojimbo2000

4

type will return “string”, “table”, “function”, but if it’s one of the Codea API elements like a vec or a matrix it will just say “userdata”

5

@yojimbo2000 - here is some code somebody worked out a while back to give more info on “userdata” types

function typeOf(x)
    if x==nil then return "nil" end
    if type(x) == "table" and x.is_a then return("class") end
    local txt 
    if typeTable==nil then
        typeTable = {
        [getmetatable(vec2()).__index  ] = "vec2", 
        [getmetatable(vec3()).__index  ] = "vec3",
        [getmetatable(color()).__index ] = "color", 
        [getmetatable(image(1,1)).__index ] = "image", 
        [getmetatable(matrix()).__index] = "matrix", 
        [getmetatable(mesh()).__index  ] = "mesh" ,
        }
    end
    local i = getmetatable(x)
    if i then txt = typeTable[i.__index] end    
    if txt then return txt end
    txt = type(x)
    return txt
end
6

whats the difference between table and class?

7

google lua table class

This is something you can learn on your own, it’s too big a subject to teach you here

I’ve also written ebooks which explain the differences, see the wiki link above

8

i mean whats x.is_a

9

that’s a property of every class (but not a table), which is why it’s used to tell the difference

10

From wiki pedia for lua:

if tonumber(a) ~= nil then
   --it's a number
end;

That should work if it’s hex like 0xFF or scientific notation 1.1e-40 as well