Convert a string to multidimensional array

Question

I have a matrix, which is read from the console. The elements are separated by spaces and new lines. How can I convert it into a multidimensional int array in c#? I have tried:

String[][] matrix = (Console.ReadLine()).Split( '\n' ).Select( t => t.Split( ' ' ) ).ToArray();

but when I click enter, the program ends and it doesn't allow me to enter more lines.

The example is:

1 2 3 4 5
2 3 4 5 6
3 4 5 6 7
4 5 6 7 8
5 6 7 8 9 

• Njol: What language is this (add it to the tags)? Also you're only reading a single line.
• Brad Christie: Maybe I've been away from console apps for too long, but how would you accept \n in a Console.ReadLine? Isn't the read terminated on \n?
• Jamiec: @BradChristie - by accepting multiple Console.ReadLine()'s in a loop
• Brad Christie: @Jamiec: Or, the answer is: "you cannot accept \n through a readline".
• John Alexiou: Is the question about how to enter the matrix from the console, or how to convert a string array into an int array? Please clarify your question.

Answer 1

int[,] Matrix = new int[n_rows,n_columns];
 for(int i=0;i<n_rows;i++){
 String input=Console.ReadLine();
 String[] inputs=input.Split(' ');
 for(int j=0;j<n_columns;j++){
 Matrix[i,j]=Convert.ToInt32(inputs[j]);
 }
 }

you can try this to load the matrix

Answer 2

First things first, Console.ReadLine() reads a single line from the input. So in order to accept multiple lines you need to do 2 things:

1. Have a loop which allows the user to continue entering lines of data. You could let them go until they leave a line blank, or you could fix it to 5 lines of input
2. Store these "lines" of data for future processing.

Assuming the user can enter any number of lines, and a blank line (just hitting enter) indicates the end of data entry something like this will suffice

List<string> inputs = new List<string>();
var endInput = false;
while(!endInput)
{
 var currentInput = Console.ReadLine();
 if(String.IsNullOrWhitespace(currentInput))
 {
 endInput = true;
 }
 else
 {
 inputs.Add(currentInput);
 }
}
// when code continues here you have all the user's input in separate entries in "inputs"

Now for turning that into an array of arrays:

var result = inputs.Select(i => i.Split(' ').ToArray()).ToArray();

That will give you an array of arrays of strings (which is what your example had). If you wanted these to be integers you could parse them as you go:

var result = inputs.Select(i => i.Split(' ').Select(v => int.Parse(v)).ToArray()).ToArray();

Answer 3

// incoming single-string matrix:
String input = @"1 2 3 4 5
2 3 4 5 6
3 4 5 6 7
4 5 6 7 8
5 6 7 8 9";
// processing:
String[][] result = input
 // Divide in to rows by \n or \r (but remove empty entries)
 .Split(new[]{ '\n', '\r' }, StringSplitOptions.RemoveEmptyEntries)
 // no divide each row into columns based on spaces
 .Select(x => x.Split(new[]{ ' ' }, StringSplitOptions.RemoveEmptyEntries))
 // case from IEnumerable<String[]> to String[][]
 .ToArray();

result:

String[][] result = new string[]{
 new string[]{ "1","2","3","4","5" },
 new string[]{ "2","3","4","5","6" },
 new string[]{ "3","4","5","6","7" },
 new string[]{ "4","5","6","7","8" },
 new string[]{ "5","6","7","8","9" }
};

Answer 4

It can be done in multiple ways

You can read a single line containing multiple numbers separated by a char, split by that char obtaining an array of ints and then you should fetch a matrix.

With out-of-the-box linq there is no trivial way for the fetching step and i think it is not really the case to use third-party libraries from codeplex like LinqLib or something.