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In Jagged Array how to add new element at top i.e at first position & remove last element

I've got a jagged array,
int[][] array = new int[][] {
new int[] { 120, 120 },
new int[] { 135, 120 },
new int[] { 150, 120 },
new int[] { 165, 120 },
new int[] { 180, 120 }
};
I'd like to add new element in it **at the top/beginning ** like:
new int[] { 105, 120 },
And also, how to remove last element from it?
Is there a way I can achieve what I want?

You're going to want Array.Copy:
Array.Copy(array, 0, array, 1, array.Length - 1);
That will leave your array looking like:
int[][] array = new int[][] {
new int[] { 120, 120 },
new int[] { 120, 120 }
new int[] { 135, 120 },
new int[] { 150, 120 },
new int[] { 165, 120 },
};
That is, we've duplicated the first element, and overwritten the last. We can then assign the first element:
array[0] = new int[] { 105, 120 };
You might prefer to use a List<int[]>:
List<int[]> list = new List<int[]>()
{
new int[] { 120, 120 },
new int[] { 135, 120 },
new int[] { 150, 120 },
new int[] { 165, 120 },
new int[] { 180, 120 }
};
Then you can insert a new element at the beginning with:
list.Insert(0, new int[] { 105, 120 });
And remove the last element with:
list.RemoveAt(list.Length - 1);
A Queue<int[]> might be better still, as adding new items to the front will be cheaper.

(C# Jagged Arrays) Howcome my jagged array counts normally, and not in elements?

In the code below, I am confused about why the line int[,][] jaggedArr = new int [ 2, 3 ] [];
requires to be counted normally, and not in elements like coders would practice.
I initially input it as int[,][] jaggedArr = new int [ 1, 2 ] [];, but wouldnt work.
Can someone please explain why this is so?
class JaggedArrays
{
static void Main (string[] args)
{
int[,][] jaggedArr = new int[2, 3][];
jaggedArr[0, 0] = new int[] { 0, 1, 2, 3, 4 };
jaggedArr[0, 1] = new int[] { 5, 6, 7, 8 };
jaggedArr[0, 2] = new int[] { 9, 10, 11, 12, 13, 14};
jaggedArr[1, 0] = new int[] { 15, 16, 17, 18, 19 };
jaggedArr[1, 1] = new int[] { 20, 21, 22, 23, 24 };
jaggedArr[1, 2] = new int[] { 25, 26, 27 };
Console.WriteLine(jaggedArr[0, 2][2]);
Console.WriteLine(jaggedArr.Length);
Console.ReadLine();
}
}

How to implement a multidimensional array shuffling in CSharp?

I wonder if it is possible to implement a general Julia\Matlab alike View function in C# that would work for arrays of any dimensions (eg [,,] and [,,,]) as they do it in array slicer\mover view. So I wonder if there is a library that provides similar functionality for CSharp multidimentional arrays or how to implement it in C#?

The solution is twofold:
Use a wrapper class that holds a reference to the master array
Use the Array base class to make it polymorphic
Wrapper
class View<T>
{
private readonly Array array;
private readonly int dim;
private readonly int slice;
public View(Array array, int dim, int slice)
{
this.array = array;
this.dim = dim;
this.slice = slice;
}
public T this[params int[] indexes]
{
get { return (T)array.GetValue(BaseIndexesFor(indexes)); }
set { array.SetValue(value, BaseIndexesFor(indexes)); }
}
private int[] BaseIndexesFor(int[] indexes)
{
if (indexes.Length != array.Rank - 1) throw new ArgumentException("indexes");
int i_index = 0;
int[] baseIndexes = new int[array.Rank];
for (int i = 0; i < baseIndexes.Length; i++)
{
baseIndexes[i] = (i == dim) ? slice : indexes[i_index++];
}
return baseIndexes;
}
}
2D example
var A = new int[,]
{
{ 1, 2, 3 },
{ 4, 5, 6 },
{ 7, 8, 9 }
};
/* View(Array array, int dim, int slice)
*
* For 2 dimensional array:
* dim=0 -> rows
* dim=1 -> columns
*/
// From second dimension slice index 1
// Or simply, take column with index 1
var B = new View<int>(A, 1, 1);
B[2] = 0;
Console.WriteLine(A[2, 1]); // 0
3D examples
var C = new int[,,]
{
{
{ 1, 2, 3 },
{ 4, 5, 6 },
{ 7, 8, 9 }
},
{
{ 11, 12, 13 },
{ 14, 15, 16 },
{ 17, 18, 19 }
},
{
{ 21, 22, 23 },
{ 24, 25, 26 },
{ 27, 28, 29 }
}
};
/* From first dimension slice index 2
* { 21, 22, 23 },
* { 24, 25, 26 },
* { 27, 28, 29 }
*/
var D = new View<int>(C, 0, 2);
D[1, 1] = 0;
Console.WriteLine(C[2, 1, 1]); // 0
/* From third dimension slice index 0
* { 1, 4, 7 },
* { 11, 14, 17 },
* { 21, 24, 27 }
*/
var E = new View<int>(C, 2, 0);
E[2, 0] = 0;
Console.WriteLine(C[2, 0, 0]); // 0

Distinct values 2d array

I have a 2D array as follows:
long[,] arr = new long[4, 4] {{ 5, 0, 0, 0 },
{ 8, 1, 1, 1 },
{ 0, 3, 0, 6 },
{ 1, 1, 1, 1 }};
How I can display distinct values form this array?

You can use Enumerable.Distinct method:
var uniqueValues = arr.Cast<long>().Distinct();

Adding many lists

If I have 100 lists (eg x1 to x100), is there a better way of expressing the final line of code?
var x1 = new List<int>() { 75 };
var x2 = new List<int>() { 95, 64 };
var x3 = new List<int>() { 17, 47, 82 };
var x4 = new List<int>() { 18, 35, 87, 10 };
var x5 = new List<int>() { 20, 04, 82, 47, 65 };
var x6 = new List<int>() { 19, 01, 23, 75, 03, 34 };
var x7 = new List<int>() { 88, 02, 77, 73, 07, 63, 67 };
//etc..
var listOfListOfInts = new List<List<int>>() { x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15 };
possibly a Dictionary and a for loop to reference all the x1..100.

As long as x1 etc. aren't referenced elsewhere, then write:
var listOfListOfInts = new List<List<int>>()
{
new List<int>() { 75 },
new List<int>() { 95, 64 },
//etc.
};
In fact you shouldn't need to reference the individual variables elsewhere since listOfListOfInts[0] is just as good as x1 for example.

Do you really need these to be of type List<T>? It looks like you're setting up preinitialized data. If you're never going to change the length of any of these "lists", you could use arrays instead; the syntax is more compact:
var listOfListOfInts = new[] {
new[] { 75 },
new[] { 95, 64 },
new[] { 17, 47, 82 },
new[] { 18, 35, 87, 10 },
new[] { 20, 04, 82, 47, 65 },
new[] { 19, 01, 23, 75, 03, 34 },
new[] { 88, 02, 77, 73, 07, 63, 67 },
// ...
};

Perhaps i'm over complicating things but you could do something like
public interface IClass1
{
IList<IList<int>> ListList { get; set; }
void AddList(List<int> nList);
}
public class Class1 : IClass1
{
public IList<IList<int>> ListList { get; set; }
public void AddList(List<int> nList)
{
ListList.Add(nList);
}
}
and then use it like:
public class Create1
{
public Create1()
{
IClass1 iClass1 = new Class1();
iClass1.AddList(new List<int>() { 75 });
}
}