Efficient way to search List of String Arrays in C#

Question

I have Structure like this,

String[] variable1= new String["ABC", "FSS" , "FSFS", "GDGDDS"];
String[] variable2= new String["SA", "GS" , "QE", "HF"];


static List<String[]> allList = new List<String[]>();;

allList .Add(variable1);
allList .Add(variable2);

When a String is provided i want to search allList and provide the result which array if were it found .

Any help archiving this in a Efficient way?

Answer 1

Both provided solutions run in linear time, which will be way too slow if you have lots of words and make lots of queries.

You can use a Dictionary. A Dictionary uses a hash table internally and it will be much, much faster.

To put all the strings in a dictionary, you can do:

Dictionary<String, String[]> dict = new Dictionary<String, String[]>();
foreach(String[] arr in allList)
    foreach(String str in arr)
        dict[str] = arr;

And then you can easily search it:

String s = "ABC";
if(dict.ContainsKey(s))
    // result is dict[s]
else
    // String is not in any array

Hope it helps!

Answer 2

You can also try this

var output=allList.Where(x=>(string.Join(",", x)+",").IndexOf(input+",")!=-1)
                  .FirstOrDefault();