Lua二维网格：嵌套表的行列遍历

-- 错误：拼字符串键，遍历全靠枚举拼键名
grid["1_1"] = 11
grid["1_2"] = 12

local grid = {}
for x = 1, 3 do
    grid[x] = {}
    for y = 1, 3 do
        grid[x][y] = x * 10 + y
    end
end
local sum = 0
for x = 1, 3 do
    for y = 1, 3 do
        sum = sum + grid[x][y]
    end
end
local label = panel:getChildByName("gridStat")
label:setString(tostring(sum))