How to find key value pair in a dictionary with values > 0 with key matching a certain string pattern?

Question

This is a dictionary,

Dictionary<string, uint> oSomeDictionary = new Dictionary<string, uint>();

oSomeDictionary.Add("dart1",1);
oSomeDictionary.Add("card2",1);
oSomeDictionary.Add("dart3",2);
oSomeDictionary.Add("card4",0);
oSomeDictionary.Add("dart5",3);
oSomeDictionary.Add("card6",1);
oSomeDictionary.Add("card7",0);

How to get the key/value pairs from oSomeDictionary with keys that starts with string "card" and has value greater than zero?

Solution 1

var result = oSomeDictionary.Where(r=> r.Key.StartsWith("card") && r.Value > 0);

for output:

foreach (var item in result)
{
    Console.WriteLine("Key: {0}, Value: {1}", item.Key, item.Value);
}

output:

Key: card2, Value: 1
Key: card6, Value: 1

Remember to inlcude using System.Linq

Solution 2

You can use Enumerable.Where to filter then dictionary elements

var result = oSomeDictionary.Where(c=>c.Key.StartsWith("card")  && c.Value > 0)

Solution 3

You can use IEnumerable.Where() and String.StartsWith() methods like;

Dictionary<string, uint> oSomeDictionary = new Dictionary<string, uint>();

oSomeDictionary.Add("dart1", 1);
oSomeDictionary.Add("card2", 1);
oSomeDictionary.Add("dart3", 2);
oSomeDictionary.Add("card4", 0);
oSomeDictionary.Add("dart5", 3);
oSomeDictionary.Add("card6", 1);
oSomeDictionary.Add("card7", 0);

var yourlist = oSomeDictionary.Where(n => n.Key.StartsWith("card") && n.Value > 0);

foreach (var i in yourlist)
{
    Console.WriteLine("Key: {0}, Value: {1}", i.Key, i.Value);
}

Output will be:

Key: card2, Value: 1
Key: card6, Value: 1

Here is a DEMO.

Solution 4

class Program
    {
        private static void Main(string[] args)
        {
            Dictionary<string, uint> oSomeDictionary = new Dictionary<string, uint>();

            oSomeDictionary.Add("dart1", 1);
            oSomeDictionary.Add("card2", 1);
            oSomeDictionary.Add("dart3", 2);
            oSomeDictionary.Add("card4", 0);
            oSomeDictionary.Add("dart5", 3);
            oSomeDictionary.Add("card6", 1);
            oSomeDictionary.Add("card7", 0);

            var result = oSomeDictionary.Where(pair => pair.Key.StartsWith("card") && pair.Value > 0 );
            foreach (var kvp in result)
            {
                Console.WriteLine("{0} : {1}",kvp.Key,kvp.Value);
            }
            Console.ReadLine();
        }
   }

Full working code above.

Solution 5

Dictionary implements <IEnumerable<KeyValuePair<TKey,TValue>>, so you can iterate through it using simple LINQ extension methods

var pairs = oSomeDictionary.Where(pair => pair.Key.StartsWith("card") && 
                                          pair.Value > 0);

Console.WriteLine (string.Join(Environment.NewLine, pairs));

prints:

[card2, 1]
[card6, 1]

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