Question

I want to use a 2-D array in C#, e.g:

string[,] a = new string[,]
{
    {"aunt", "AUNT_ID"},
    {"Sam", "AUNT_NAME"},
    {"clozapine", "OPTION"},
};

My requirement is that when I pass "aunt" to this array I want to get corresponding AUNT_ID from the 2-D array.

Answer 1

As others have said, a Dictionary<string, string> would be better – and you can use a collection initializer to create it simply:

Dictionary<string, string> dictionary = new Dictionary<string, string>
{
    {"ant", "AUNT_ID"},
    {"Sam", "AUNT_NAME"},
    {"clozapine", "OPTION"},
};

If you’re confident that your key is in the dictionary, and you’re happy for an exception to be thrown otherwise:

string value = dictionary[key];

or if it might not be:

string value;
if (dictionary.TryGetValue(key, out value))
{
    // Use value here
}
else
{
    // Key wasn't in dictionary
}

If you really need to use an array, if you can change it to a multidimensional array (string[][]), you can use:

// Will throw if there are no matches
var value = array.First(x => x[0] == key)[1];

Or again to be more circumspect:

var pair = array.FirstOrDefault(x => x[0] == key);
if (pair != null)
{
    string value = pair[1];
    // Use value here
}
else
{
    // Key wasn't in dictionary
}

LINQ unfortunately doesn’t work quite as well on rectangular arrays. It probably wouldn’t be too hard to write a method to allow it to be treated “somewhat” like an array of arrays, admittedly…