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Check whether the Dictionary has the specified key or not in C#
To check whether the Dictionary<TKey,TValue> has the specified key or not, the code is as follows −
Example
using System; using System.Collections.Generic; public class Demo { public static void Main() { Dictionary<string, string> dict = new Dictionary<string, string>(); dict.Add("One", "John"); dict.Add("Two", "Tom"); dict.Add("Three", "Jacob"); dict.Add("Four", "Kevin"); dict.Add("Five", "Nathan"); Console.WriteLine("Count of elements = "+dict.Count); Console.WriteLine("
Key/value pairs..."); foreach(KeyValuePair<string, string> res in dict) { Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value); } if (dict.ContainsKey("Three")) Console.WriteLine("Key found!"); else Console.WriteLine("Key isn't in the dictionary!"); dict.Clear(); Console.WriteLine("Cleared Key/value pairs..."); foreach(KeyValuePair<string, string> res in dict) { Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value); } Console.WriteLine("Count of elements now = "+dict.Count); } }
Output
This will produce the following output −
Count of elements = 5 Key/value pairs... Key = One, Value = John Key = Two, Value = Tom Key = Three, Value = Jacob Key = Four, Value = Kevin Key = Five, Value = Nathan Key found! Cleared Key/value pairs... Count of elements now = 0
Example
Let us see another example −
using System; using System.Collections.Generic; public class Demo { public static void Main() { Dictionary<string, string> dict = new Dictionary<string, string>(); dict.Add("One", "John"); dict.Add("Two", "Tom"); dict.Add("Three", "Jacob"); dict.Add("Four", "Kevin"); dict.Add("Five", "Nathan"); Console.WriteLine("Count of elements = "+dict.Count); Console.WriteLine("
Key/value pairs..."); foreach(KeyValuePair<string, string> res in dict) { Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value); } if (dict.ContainsKey("mykey")) Console.WriteLine("Key found!"); else Console.WriteLine("Key isn't in the dictionary!"); dict.Clear(); Console.WriteLine("Cleared Key/value pairs..."); foreach(KeyValuePair<string, string> res in dict) { Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value); } Console.WriteLine("Count of elements now = "+dict.Count); } }
Output
This will produce the following output −
Count of elements = 5 Key/value pairs... Key = One, Value = John Key = Two, Value = Tom Key = Three, Value = Jacob Key = Four, Value = Kevin Key = Five, Value = Nathan Key isn't in the dictionary! Cleared Key/value pairs... Count of elements now = 0
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