Matrix Operator

Matrix Operator.cs

using System;
using System.Collections.Generic;
using System.Linq;

public class Matrix_Operator
{
    public static void Main()
    {
        List<List<int>> matrix = GetMatrix();
        while (true)
        {
            string input = Console.ReadLine();
            if (input == "end") break;

            string[] data = input.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            string command = data[0];
            if (command == "remove")        matrix = RemoveElements(matrix, data);
            else if (command == "swap" )    matrix = SwapRows(matrix, data);
            else if (command == "insert")   matrix = InsertElementInRow(matrix, data);
        }
        PrintMatrix(matrix);
    }

    private static List<List<int>> InsertElementInRow(List<List<int>> matrix, string[] data)
    {
        int row = int.Parse(data[1]);
        int element = int.Parse(data[2]);
        bool isValidIndex = row >= 0 && row < matrix.Count;
        if (isValidIndex)
        {
            List<int> elements = matrix[row];
            elements.Insert(0, element);
            matrix[row] = elements;
        }
        //PrintMatrix(matrix);
        return matrix;
    }

    private static List<List<int>> SwapRows(List<List<int>> matrix, string[] data)
    {
        int row1 = int.Parse(data[1]);
        int row2 = int.Parse(data[2]);
        bool isValidIndex = row1 >= 0 && row1 < matrix.Count &&
                            row2 >= 0 && row2 < matrix.Count;
        if (isValidIndex)
        {
            List<int> elementsRow1 = matrix[row1];
            List<int> elementsRow2 = matrix[row2];
            matrix[row1] = elementsRow2;
            matrix[row2] = elementsRow1;
        }
        //PrintMatrix(matrix);
        return matrix;
    }

    private static List<List<int>> RemoveElements(List<List<int>> matrix, string[] data)
    {
        string type = data[1];  
        string rowCol = data[2];
        int index = int.Parse(data[3]);
        bool isValidRowIndex = index >= 0 && index < matrix.Count;
        if (rowCol == "row" && isValidRowIndex)
        {
            List<int> elements = matrix[index];
            if (type == "positive")         elements.RemoveAll(x => x >= 0);    // NB! =
            else if (type == "negative")    elements.RemoveAll(x => x < 0);
            else if (type == "odd")         elements.RemoveAll(x => x % 2 != 0);
            else if (type == "even")        elements.RemoveAll(x => x % 2 == 0);
            matrix[index] = elements;       // empty rows are not deleted
        }
        else if (rowCol == "col")
        {
            for (int row = 0; row < matrix.Count; row++)    // valid row index
            {
                bool isValidColIndex = index >= 0 && index < matrix[row].Count;
                if (isValidColIndex)
                {
                    List<int> elements = matrix[row];
                    if (type == "positive" && elements[index] >= 0)         elements.RemoveAt(index);   // NB! =
                    else if (type == "negative" && elements[index] < 0)     elements.RemoveAt(index);
                    else if (type == "odd" && elements[index] % 2 != 0)     elements.RemoveAt(index);
                    else if (type == "even" && elements[index] % 2 == 0)    elements.RemoveAt(index);
                    matrix[row] = elements;
                }
            }
        }
        //PrintMatrix(matrix);
        return matrix;
    }

    private static void PrintMatrix(List<List<int>> matrix)
    {
        for (int row = 0; row < matrix.Count; row++)
            Console.WriteLine(string.Join(" ", matrix[row]));
    }

    private static List<List<int>> GetMatrix()
    {
        int rows = int.Parse(Console.ReadLine());
        List<List<int>> matrix = new List<List<int>>();
        for (int row = 0; row < rows; row++)
        {
            List<int> elements = Console.ReadLine()
                .Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)
                .Select(int.Parse).ToList();
            matrix.Add(elements);
        }
        return matrix;
    }
}