initializing multi-dim string arrays

Question

Stuck here trying to initialize an array (c#) using a loop. The number of rows will change depending. I need to get back two values that I am calculating earlier in the program startweek, and endweek. Lots of examples on building int arrays using loops but nothing I can find re dynamic strings and multi dim arrays.

Thanks

how do I set the values for col1 in string[,] arrayWeeks = new string[numWeeks, col1]; Is that clearer?

Answer 1

There are two types of what you might call "multidimensional" arrays in C#. There are genuine multidimensional arrays:

string[,] array = new string[4, 4];
array[0, 0] = "Hello, world!";
// etc.

There are also jagged arrays. A jagged array an array whose elements are also arrays. The "rows" in a jagged array can be of different lengths. An important note with jagged arrays is that you have to manually initialize the "rows":

string[][] array = new string[4][];
for(int i = 0; i < 4; i++) {
    array[i] = new string[4];
}
array[0][0] = "Hello, world!";

Answer 2

If the number of rows change depending on some factor (not fixed), it would be better to use a container, such as a List (see list on the MSDN). You can nest a list within a list to create a multi-dimensional list.

Answer 3

(Thanks for the clarification.) You can do a multidimensional initializer like so:

string[,] arrayWeeks = new string[,] { { "1", "2" }, { "3", "4" }, { "5", "6" }, { "7", "8" } };

Or, if your array is jagged:

string[][] arrayWeeks = new string[][] 
{
    new string[] {"1","2","3"},
    new string[] {"4","5"},
    new string[] {"6","7"},
    new string[] {"8"}
};

If you're in a loop, I'm guessing you want jagged. And instead of initializing with values, you may want to call arrayWeeks[x] = new string[y]; where x is the row you're adding and y is the number of elements in that row. Then you can set each value: arrayWeeks[x][i] = ... where you are setting the ith element in the row. Your initial declaration of the array would be string[][] arrayWeeks = new string[numRows][];

So, to summarize, you probably want something that looks like this:

    int numRows = 2;
    string[][] arrayWeeks = new string[numRows][];
    arrayWeeks[0] = new string[2];
    arrayWeeks[0][0] = "hi";
    arrayWeeks[0][1] = "bye";
    arrayWeeks[1] = new string[1];
    arrayWeeks[1][0] = "aloha";

But, obviously, within your loop.