将嵌套的JSON转换为CSV

Question

我正在将一个超过10级的嵌套JSON对象转换为C#.NET中的CSV文件.

我一直在使用JavaScriptSerializer().Deserialize<ObjectA>(json)或XmlNode xml = (XmlDocument)JsonConvert.DeserializeXmlNode(json)打破对象.使用这些对象,我可以进一步写入CSV文件.但是现在JSON对象进一步扩展.大多数数据并没有真正使用,所以我更喜欢原始数据转储.

是否更简单的方法我可以将数据转储为csv格式而不声明结构？

示例JSON

{
"F1":1,
"F2":2,
"F3":[
    {
        "E1":3,
        "E2":4
    },
    {
        "E1":5,
        "E2":6
    },  
    {
        "E1":7,
        "E2":8,
        "E3":[
            {
                "D1":9,
                "D2":10
            }
        ]
    },      
]
}   

我期望的CSV输出是

F1,F2,E1,E2,D1,D2
1,2
1,2,3,4
1,2,5,6
1,2,7,8,9,10

Answer 1

您的请求中存在不一致:您希望为具有子项的根对象生成一行,但您不希望为该"F3[2]"对象生成一行,该行也具有子项.所以听起来你的规则是"为具有至少一个原始值属性的对象打印一行,只要该对象是根对象或者没有至少具有一个原始值属性的后代对象" .这有点棘手,但可以使用LINQ to JSON

        var obj = JObject.Parse(json);

        // Collect column titles: all property names whose values are of type JValue, distinct, in order of encountering them.
        var values = obj.DescendantsAndSelf()
            .OfType<JProperty>()
            .Where(p => p.Value is JValue)
            .GroupBy(p => p.Name)
            .ToList();

        var columns = values.Select(g => g.Key).ToArray();

        // Filter JObjects that have child objects that have values.
        var parentsWithChildren = values.SelectMany(g => g).SelectMany(v => v.AncestorsAndSelf().OfType<JObject>().Skip(1)).ToHashSet();

        // Collect all data rows: for every object, go through the column titles and get the value of that property in the closest ancestor or self that has a value of that name.
        var rows = obj
            .DescendantsAndSelf()
            .OfType<JObject>()
            .Where(o => o.PropertyValues().OfType<JValue>().Any())
            .Where(o => o == obj || !parentsWithChildren.Contains(o)) // Show a row for the root object + objects that have no children.
            .Select(o => columns.Select(c => o.AncestorsAndSelf()
                .OfType<JObject>()
                .Select(parent => parent[c])
                .Where(v => v is JValue)
                .Select(v => (string)v)
                .FirstOrDefault())
                .Reverse() // Trim trailing nulls
                .SkipWhile(s => s == null)
                .Reverse());

        // Convert to CSV
        var csvRows = new[] { columns }.Concat(rows).Select(r => string.Join(",", r));
        var csv = string.Join("\n", csvRows);

        Console.WriteLine(csv);

运用

public static class EnumerableExtensions
{
    // http://stackoverflow.com/questions/3471899/how-to-convert-linq-results-to-hashset-or-hashedset
    public static HashSet<T> ToHashSet<T>(this IEnumerable<T> source)
    {
        return new HashSet<T>(source);
    }
}

哪个输出:

F1,F2,E1,E2,D1,D2
1,2
1,2,3,4
1,2,5,6
1,2,7,8,9,10