LINQ dictionary to jagged array?

There is a method that returns 2D array, this method querying a dictionary from LINQ query and trying to store keys and values in 2D array.

But I am not able to do that

public string[][] GetRecordFields(string selectedRecord)
    {

        var recordFields = (from record in _recordMasterList
                            where record.Item1 == selectedRecord
                            select new 
                            {
                                record.Item2.Keys,
                                record.Item2.Values
               开发者_Go百科             }).ToArray();
      return recordFields;       
  }

But its failed, is there any way?

EDIT: Type of _recordMasterList

List<Tuple<string, Dictionary<string, string>>> _recordMasterList;

Create a string array instead of an object in the query, then the ToArray will return an array of arrays:

public string[][] GetRecordFields(string selectedRecord) {
  return (
    from record in _recordMasterList
    where record.Item1 == selectedRecord
    select new string[] {
      record.Item2.Keys,
      record.Item2.Values
    }
  ).ToArray();
}

In your select you need to create a string array (new []). In your example you were creating a new anonymous type.

public string[][] GetRecordFields(string selectedRecord)
{
    string[][] recordFields = (from record in _recordMasterList
                        where record.Key == selectedRecord
                        select new []
                        {
                            record.Key,
                            record.Value
                        }).ToArray();

    return recordFields;
}

(I've changed the code slightly to deal with a _recordMasterList of type Dictionary<string, string>. Also, in code like this I find it clearer to declare my variable type explicitly, rather than relying on implicit typing. That said, with arrays I prefer to use implicit array typing - new [] rather than new string[].)

Not a one liner LINQ magic but here it is:

/// <summary>
/// Converts dictionary to 2d string array
/// </summary>
/// <param name="Dictionary">Dictionary to be converted</param>
/// <returns>2D string Array</returns>
private string[,] ConvertDictionaryTo2dStringArray(Dictionary<string, string> Dictionary)
{
    string[,] stringArray2d = new string[2, Dictionary.Count];
    int i = 0;

    foreach (KeyValuePair<string, string> item in Dictionary)
    {
        stringArray2d[0, i] = item.Key;
        stringArray2d[1, i] = item.Value;
        i++;
    }

    return stringArray2d;
}

A more generic version with reversed dimensions:

private object[,] Dictionary2Array(Dictionary<object, object> dic)
{
    object[,] arr = new object[dic.Count, 2];
    int i = 0;

    foreach (KeyValuePair<object, object> item in dic)
    {
        arr[i, 0] = item.Key;
        arr[i, 1] = item.Value;
        i++;
    }

    return arr;
}

Your question is still a little bit confussing. Is this the behaviour you are looking for?

(I know that this answer could be optimised a lot, but it seams the easiest way to figue out what you want.)

public string[,] GetRecordFields(string selectedRecord)
{
    //List<Tuple<string, Dictionary<string, string>>> _recordMasterList;

    List<Dictionary<string, string>> selectedRecords
        = (from record in _recordMasterList
            where record.Item1 == selectedRecord
            select record.Item2)
            .ToList();

    int totalNumberOfRecords = 0;

    foreach(Dictionary<string, string> d in selectedRecords)
    {
        totalNumberOfRecords += d.Count();
    }

    string[,] result = new string[2, totalNumberOfRecords];

    int i = 0;
    foreach(Dictionary<string, string> d in selectedRecords)
    {
        foreach(KeyValuePair<string, string> kvp in d)
        {
            result[0,i] = kvp.Key;
            result[1,i] = kvp.Value;
            ii++;
        }
    }

    return result;
}