如何将DataFrame生成的资助数据改为无命名对象序列用于JSON序列化？

我有一个Julia函数getgrants，接收DataFrame作为输入，生成嵌套Dict来表示一系列资助信息，最终要把这个Dict嵌套进更大的层级里生成JSON文件。但目前序列化后的JSON里，资助项带了不必要的数字枚举键，我想改成无命名对象序列（也就是JSON数组），有没有简便的实现方法？

原函数代码 #

function getgrants(Grantrows)
    if nrow(Grantrows)==0
        return nothing
    end
    Grants = Dict()
    let j = 0
        for GCSGrants in eachrow(Grantrows)
            j += 1
            Grants[j] = Dict(
                "GrantID" => GCSGrants.Grant_ID,
                "GrantDate" => GCSGrants.Grant_Date,
                "GrantAmount" => GCSGrants.Grant_Amount,
                "GrantTitle" => GCSGrants.Grant_Title,
                "GrantDistributor" => GCSGrants.Grant_Distributor,
            )
        end
    end
    return Grants
end

当前序列化后的JSON片段 #

"Grants": {
   "1": {
       "GrantTitle": "Recipient 1",
       "GrantDate": "2022-03-16",
       "GrantAmount": 600000,
       "GrantDistributor": "Distributor 1",
       "GrantID": "ID789"
   },
   "2": {
       "GrantTitle": "Recipient 2",
       "GrantDate": "2020-09-02",
       "GrantAmount": 250000,
       "GrantDistributor": "Distributor 2",
       "GrantID": "ID456"
   },
   "3": {
       "GrantTitle": "Recipient 3",
       "GrantDate": "2020-06-25",
       "GrantAmount": 448770,
       "GrantDistributor": "Distributor 3",
       "GrantID": "ID123"
   }
}

解决方法 #

核心就是把原来存资助项的Dict换成Julia的Vector（数组）——因为JSON的数组对应Julia的Vector，序列化后自然就是无键的对象序列。

修改后的函数代码：

function getgrants(Grantrows)
    Grants = Vector{Dict}()
    for GCSGrants in eachrow(Grantrows)
        push!(Grants, Dict(
            "GrantID" => GCSGrants.Grant_ID,
            "GrantDate" => GCSGrants.Grant_Date,
            "GrantAmount" => GCSGrants.Grant_Amount,
            "GrantTitle" => GCSGrants.Grant_Title,
            "GrantDistributor" => GCSGrants.Grant_Distributor,
        ))
    end
    # 如果空数据时要返回空数组而非nothing，直接返回Grants即可；要是想保持返回nothing，加个判断：
    # isempty(Grants) ? nothing : Grants
    return Grants
end

修改后的JSON效果 #

序列化后会变成标准的JSON数组结构：

"Grants": [
   {
       "GrantTitle": "Recipient 1",
       "GrantDate": "2022-03-16",
       "GrantAmount": 600000,
       "GrantDistributor": "Distributor 1",
       "GrantID": "ID789"
   },
   {
       "GrantTitle": "Recipient 2",
       "GrantDate": "2020-09-02",
       "GrantAmount": 250000,
       "GrantDistributor": "Distributor 2",
       "GrantID": "ID456"
   },
   {
       "GrantTitle": "Recipient 3",
       "GrantDate": "2020-06-25",
       "GrantAmount": 448770,
       "GrantDistributor": "Distributor 3",
       "GrantID": "ID123"
   }
]

内容的提问来源于stack exchange，提问作者Tim Gebbels