Is there an efficient and elegant way to truncate number like this in Lua?

What I want to do

What I want to do is really simple. I want use Lua to check lines in a Plist file.

Let's say if a line in Plist, is <integer>-1.00</integer>, I need to cut the .00 off to make it be <integer>-1</integer>.

What I did

I use a function to read the whole file content and do line by line check and replace.

local function doLineClean( cont )
    newcont = ''
    string.gsub( cont, "(.-)\r?\n", function(line)
        if string.match( line, "<integer>.-<%/integer>" ) then
            string.gsub( line, "<.->(.-)<.->", function(v)
            a, b = string.find(v,"%..*")
            if a and b then
                v = string.sub( v, 0, a - 1 )
            end
            line = "\t\t<integer>"..v.."</integer>"
            end  )
        end
        newcont = newcont .. line .. '\n'
    end  )
    return newcont
end

My question

Is there an more efficient and elegant way to do the same job?