This question is related to the code sample in the answer here (https://stackoverflow.com/a/70694640/2287576).

I now have this constructor:

public List<MSAHistoryItemStudent>[] StudentItems { get; set; }
public MSAHistoryWeek()
{
    TalkItems = Enumerable.Range(1, 6).Select(x => new MSAHistoryItemTalk()).ToList();
    Teaching = Enumerable.Range(1, 3).Select(x => string.Empty).ToList();
    StudentItemStudyNumbers = Enumerable.Range(1, 5).Select(x => string.Empty).ToList();
    StudentItemDescriptions = Enumerable.Range(1, 5).Select(x => string.Empty).ToList();

    StudentItems = new List<MSAHistoryItemStudent>[]
    {
        new List<MSAHistoryItemStudent>(),
        new List<MSAHistoryItemStudent>(),
        new List<MSAHistoryItemStudent>(),
    };

    foreach(var studentitems in StudentItems)
    {
        for(int i = 0; i < 5; i  )
        {
            studentitems.Add(new MSAHistoryItemStudent());
        }
    }
}

I can't work out the Enumerable.Range approach to pre-create StudentItems how I want:

• I want an array of 3 List<MSAHistoryItemStudent>.
• I want each of these arrays to have 5 MSAHistoryItemStudent elements.

CodePudding user response：

As there is a relatively low number of lists, you can replace your calls to new with a call to Enumerable.Range:

StudentItems = new 
{
    Enumerable.Range(1, 5).Select(x => new MSAHistoryItemStudent()).ToList(),
    Enumerable.Range(1, 5).Select(x => new MSAHistoryItemStudent()).ToList(),
    Enumerable.Range(1, 5).Select(x => new MSAHistoryItemStudent()).ToList(),
};

Incidentally, if you put this somewhere:

public static List<T> MakeN<T>(int n) where T:new()
  => Enumerable.Range(1,n).Select(x => new T()).ToList();

Then you can simplify those calls some:

TalkItems = MakeN<MSAHistoryItemTalk>(6);
Teaching = new string[3].ToList();

StudentItems = new
{
    MakeN<MSAHistoryItemStudent>(5),
    MakeN<MSAHistoryItemStudent>(5),
    MakeN<MSAHistoryItemStudent>(5),
};

And everywhere else you're using Enumerable.Range.Select..

... apart from where you do it to string (for which I've given an alternative form).

CodePudding user response：

Just nest another one of those Enumerable.Range(...)... calls in the Select call.

StudentItems =
    Enumerable.Range(1, 3).Select(x =>
        Enumerable.Range(1, 5).Select(y =>
            new MSAHistoryItemStudent()
        ).ToList()
    ).ToArray();