dictionary key object c# code example

Example 1: dictionary c#

var cities = new Dictionary<string, string>(){
	{"UK", "London, Manchester, Birmingham"},
	{"USA", "Chicago, New York, Washington"},
	{"India", "Mumbai, New Delhi, Pune"}
};

Example 2: dictionary c#

var cities = new Dictionary<string, string>(){
	{"UK", "London, Manchester, Birmingham"},
	{"USA", "Chicago, New York, Washington"},
	{"India", "Mumbai, New Delhi, Pune"}
};

Console.WriteLine(cities["UK"]); //prints value of UK key
Console.WriteLine(cities["USA"]);//prints value of USA key
//Console.WriteLine(cities["France"]); // run-time exception: Key does not exist

//use ContainsKey() to check for an unknown key
if(cities.ContainsKey("France")){  
    Console.WriteLine(cities["France"]);
}

//use TryGetValue() to get a value of unknown key
string result;

if(cities.TryGetValue("France", out result))
{
    Console.WriteLine(result);
}

//use ElementAt() to retrieve key-value pair using index
for (int i = 0; i < cities.Count; i++)
{
    Console.WriteLine("Key: {0}, Value: {1}", 
                                            cities.ElementAt(i).Key, 
                                            cities.ElementAt(i).Value);
}