Specifying 2 dimensional array of strings elegantly

Question

I am trying to instantiate a 2 dimensional array of strings. My issues is that the 2nd dimensions of the array are not all the same and I am not sure how to specify this code wise.

These variable specify electrical boards. There are 4 boards, each with a varying number of contacts. For each contact there is a description about its purpose.

int numBoards = 4;
String[] boardNames = {"FirstBoard", "Second Board", "Third Board", "Fourth Board"};
int[] numContacts = { 32, 24, 48, 32 };
String[][] descriptions = new String[numBoards][???];

How can I specify that my 2nd dimensions of the descriptions array are of varying sizes; the sizes specified in numContacts?

Is this the only way to do it? Or is there something more elegant?

int numBoards = 4;
String[] boardNames = {"FirstBoard", "Second Board", "Third Board", "Fourth Board"};
int[] numContacts = { 32, 24, 48, 32 };

String[] desc1 = new String[numContacts[0]];
String[] desc2 = new String[numContacts[1]];
String[] desc3 = new String[numContacts[2]];
String[] desc4 = new String[numContacts[3]];
String[][] descriptions = new String[numBoards][];
descriptions[0] = desc1;
descriptions[1] = desc2;
descriptions[2] = desc3;
descriptions[3] = desc4;

If that becomes larger you'd probably start putting the data into a file and then parse the file. — Thomas Weller
– Thomas Weller, Commented May 9, 2014 at 14:09
You used array initialized syntax for the inner arrays. Do the same for the containing array. — Eric Lippert
– Eric Lippert, Commented May 9, 2014 at 14:22
That said, this whole thing looks like a bad design. Make a class to represent boards. — Eric Lippert
– Eric Lippert, Commented May 9, 2014 at 14:24

Charleh · Accepted Answer · 2014-05-09 14:11:07Z

2

You could use the object initialiser syntax to populate your array:

string[][] strings =
{
    new[] { "Fred", "Bob" },
    new[] { "Anne", "Steve", "John" }
};

If by elegant you mean syntax wise

answered May 9, 2014 at 14:11

Charleh

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Comments

Chris Hinton · Accepted Answer · 2014-05-09 14:17:29Z

2

I think the more elegant solution would to not use a 2d array at all, but an array of Board classes.

public class Board {
  public Board(String name, int contactCount) {
    Name = name;
    Contacts = new List<String>(contactCount);
  }

  public String Name { get; set; }
  public List<String> Contacts { get; set; }
  ...
}

answered May 9, 2014 at 14:17

Chris Hinton

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1 Comment

Robert Snyder Over a year ago

ninja'd me :P that is what I was going to suggest to since it is much easier on the eyes to read, and easier to manage too.

D Stanley · Accepted Answer · 2014-05-09 14:25:05Z

1

You can use a Linq query to generate the jagged array:

int[] numContacts = { 32, 24, 48, 32 };

String[][] descriptions = numContacts.Select(c => new string[c]).ToArray();

edited May 9, 2014 at 14:25

answered May 9, 2014 at 14:10

D Stanley

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3 Comments

AnotherUser Over a year ago

A pure 2-d would be something with the same values for each 2nd dimension? // So that will work to find both the first and second dimensions for the array?

D Stanley Over a year ago

@user1596244 I would say a 2-D array is a "rectangular" array, but it's a semantic issue and not relevant to your question, so I'll remove that part. The code I posted works to generate a jagged array.

AnotherUser Over a year ago

Makes sense, I guess I just never heard it. // Thanks, worked perfectly!

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