Lua之Next用法

想输出 “1，2，3"的时候 以前的写法都是

local testTable ={"1","2","3"}
local step = 1
local tableCount = #testTable

local destStr = ""
for key, var in pairs(testTable) do
   destStr  = destStr..var
   if step ~= tableCount  then 
destStr  = destStr..","
   end
   step  = step  + 1
end

知道Next之后就简便一些

local testTable ={"1","2","3"}
local destStr = ""
for key, var in pairs(testTable) do
    destStr  = destStr..var
    if  next(testTable,key)  then 
        destStr  = destStr..","
    end
end
print ("destStr==="..destStr)