I want to use a string to store values in a table,but i'm not sure how to use it. Anyone help? [closed]

Since there is no TableValue objects in Roblox, i decided to use StringValues to store multiple values of a table so i can use it later. Here is an example:

function convert(t)
    local string=t[1]..','
    for i=2,#t-1 do
        string=string..t[i]..','
    end
    string=string..t[#t]
    return string
end

knifes=convert({1,3,4,5,8})

Here's the trouble: I don't know how to convert the string into a table again. I can't use tonumber function because it will return nil...