Introduction and simple usage of hash table (Hashtable) in C #

Keys are usually used for quick search, and keys are case-sensitive. values are used to store values corresponding to keys. In Hashtable, key/value pairs are of the object type, hashtable supports any type of key/value pairs <BR> Add a key/value key-value pair in the hash table: HashtableObject. add (key, value );
Remove a key/value pair in the hash table: HashtableObject. Remove (key );
Remove all elements from the hash table: HashtableObject. Clear ();
Determine whether the hash table Contains the specified key: HashtableObject. Contains (key );
The following console contains all the preceding operations:

Copy codeThe Code is as follows: using System;

Using System. Collections; // This namespace must be introduced when Hashtable is used.

Class hashtable

{

Public static void Main ()

{

Hashtable ht = new Hashtable (); // create a Hashtable instance

Ht. Add ("E", "e"); // Add key/value pairs

Ht. Add ("A", "");

Ht. Add ("C", "c ");

Ht. Add ("B", "B ");

String s = (string) ht ["A"];

If (ht. Contains ("E") // checks whether the hash table Contains a specific key. The return value is true or false.

Console. WriteLine ("the E key: exist ");

Ht. Remove ("C"); // Remove a key/value pair

Console. WriteLine (ht ["A"]); // output
}

// DictionaryEntry Object is required to traverse the hash table. The Code is as follows:

For (DictionaryEntry de in ht) // ht is a Hashtable instance.
{
Console. WriteLine (de. Key); // de. Key corresponds to the key-value Pair
Console. WriteLine (de. Value); // de. Key corresponds to the key/value Key-value Pair Value
}
}