sorting - 使用lua对嵌套表进行排序

Question

我有下表:

{
  STANDBY = {
    timeout = "10",
    mode = "0"
  },
  RTP = {
    minport = "10000",
    maxport = "10010"
  }
}

我想按字母顺序排序，所以结果表应该是这样的:

{
  RTP = {
    maxport = "10010",
    minport = "10000"
  },
  STANDBY = {
    mode = "0",
    timeout = "10"
  },
}

你能帮我吗？

Answer 1

引用以下内容:Programming in Lua : 19.3 .

A common mistake is to try to order the indices of a table. In a table, the indices form a set, and have no order whatsoever. If you want to order them, you have to copy them to an array and then sort the array.

If you traverse a table with pairs(), the names appear in an arbitrary order. However, you cannot sort them directly, because these names are keys of the table.

同一页面上还提到了解决方法。

local tableVarName = {
    STANDBY = {
        timeout = "10",
        mode = "0"
    },
    RTP = {
        minport = "10000",
        maxport = "10010"
    }
}
function pairsByKeys (t, f)
  local a = {}
  for n in pairs(t) do table.insert(a, n) end
  table.sort(a, f)
  local i = 0      -- iterator variable
  local iter = function ()   -- iterator function
    i = i + 1
    if a[i] == nil then return nil
    else return a[i], t[a[i]]
    end
  end
  return iter
end
for name, line in pairsByKeys(tableVarName) do
  print(name, line)
end