How to check if a number have integer representation

Question

How to check if a number have integer representation

number can be a float or double

Answer 1

In Lua 5.3+, use math.tointeger:

math.tointeger (x)

If the value x is convertible to an integer, returns that integer. Otherwise, returns nil.

Answer 2

Maybe check numbers for dot to see if it is a float or integer?

Then check this out...

dotchk=function(...);
local args={...}
assert(args[1],'Need argument')
local _,b=tostring(args[1]):gsub('%.','') -- Check for dot

if b>0 then
 print('floating point found in:',args[1])
 return true
else
 print('No dot in:',args[1])
 return false
end

end

Three examples...

>dotchk(math.pi)
floating point found in:    3.1415926535898
true
>dotchk(math.maxinteger)
No dot in:  9223372036854775807
false
>dotchk(math.mininteger)
No dot in:  -9223372036854775808
false