How do I add a string array within a string array array in a string list?

Question

I have a string[,] with a set amount of string[] that stay the same and want to pick a few of them and put them in a list<string[]> (I use a list to make it ever extendable). But the list<string[]> won't accept any string[] from the string[,].

string[,] testArray =
{
    {"testValue1", "testValue1.1"}
    {"testValue2", "testValue2.1"}
    {"testValue3", "testValue3.1"}
}

List<string[]> testList = new List<string[]>();

testList.Add(testArray[1]) //error: wrong number of indicaters inside[]
testList.Add(testArray[1,1]) //error: cannot convert from string to string[]

string[,] is not array of array, it is 2D array. Maybe you want string[][]? There the testArray is string matrix with width 2 and height 3 and there is not easy way to iterate single row/column, you have to do your own for loop for that. (or maybe extension method) — Ondřej Kubíček
– Ondřej Kubíček, Commented Feb 10, 2019 at 10:28

Michael · Accepted Answer · 2019-02-17 10:06:12Z

1

What you have there is a 2D array, not a jagged array (array of arrays).

You can't directly reference the entire row of a 2D array (unlike a jagged array). The easy solution is to use a jagged array string[][] but if you expressly don't want to do that you can achieve the same thing by looping over the row of the 2D array yourself and buffering it into another array

string[,] testArray =
{
    {"testValue1", "testValue1.1"},
    {"testValue2", "testValue2.1"},
    {"testValue3", "testValue3.1"}
};

List<string[]> testList = new List<string[]>();
string[] arrayRow = new string[testArray.GetLength(1)]; // zero index dimension to get length of

int i = 0; // row to copy
for (int j = 0; j < testArray.GetLength(1); j++) { // loop over row
    arrayRow[j] = testArray[i, j];
}
testList.Add(arrayRow); // {"testValue1", "testValue1.1"} added to list

edited Feb 17, 2019 at 10:06

answered Feb 10, 2019 at 10:46

Michael

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Comments

Mehrdad Dowlatabadi · Accepted Answer · 2019-02-10 10:44:47Z

0

Either you can use jagged array or for loop for 2d array:

Jagged array:

new string[] {"testValue1", "testValue1.1"},
new string[] {"testValue2", "testValue2.1"},
new string[] {"testValue3", "testValue3.1"}
};

List<string[]> testList = new List<string[]>();

testList.Add(testArray[1]); //second row of jagged array

2d array:

string[,] testArray =
{
 {"testValue1", "testValue1.1"},
 {"testValue2", "testValue2.1"},
 {"testValue3", "testValue3.1"}
};

List<string[]> testList = new List<string[]>();
string[] secnd_rw=new string[testArray.GetLength(1)] ;
for (int i = 0; i < testArray.GetLength(1); i++)
{
    secnd_rw[i] = testArray[1,i];
}
testList.Add(secnd_rw); //second row of 2d array

answered Feb 10, 2019 at 10:44

Mehrdad Dowlatabadi

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Comments

Johnny · Accepted Answer · 2019-02-10 15:00:25Z

I have a string[,] with a set amount of string[]

This is actually not true because you are using the multidimensional array instead of the jagged array. If you are using the [,] you could not out of the box take the whole row as if you are using [][].

Jagged

string[][] testArray =
{
    new [] {"testValue1", "testValue1.1"},
    new [] {"testValue2", "testValue2.1"},
    new [] {"testValue3", "testValue3.1"}
};

Console.WriteLine(string.Join(", ", testArray[0])); //testValue1, testValue1.1

2D Array

string[,] testArray =
{
    {"testValue1", "testValue1.1"},
    {"testValue2", "testValue2.1"},
    {"testValue3", "testValue3.1"}
};

Console.WriteLine(string.Join(", ", testArray.GetColumn(0))); //testValue1, testValue1.1

public static class ArrayExt
{
    public static IEnumerable<string> GetColumn(this string[,] array, int column)
    {
        return Enumerable.Repeat(column, array.GetLength(1))
            .Zip(Enumerable.Range(0, array.GetLength(1)), (x,y) => new { X = x, Y = y })
            .Select(i => array[i.X, i.Y]);
    }
}

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