This document discusses dictionaries, hash tables, and hash sets in C#. It describes dictionaries as a generic collection of key-value pairs where each key is unique. It lists common dictionary methods like adding, removing, finding, and replacing elements. Hash tables are described as storing key-value pairs where keys are used to locate values. Common hash table properties and methods are listed. Finally, it defines hash sets as ensuring there are no duplicate elements like strings in a collection.

2. Agenda

3. What is C# Dictionaries?
Methods in C# Dictionaries
What is C# Hash-table?
Properties of C# Hash-table
Methods in C# Hash-table
C# Hash-set
Implementation

4. What are C# Dictionaries?

5. What are C# Dictionaries?
A generic namespace is a class that can include any
type of data in the form of keys and values.
Dictionary is a class defined in the System.Collections
package.
The Dictionary class in C# is a generic collection of key-
value pairs.
Each key in the collection must be unique.
Syntax:
Dictionary<string, string> Dict = new Dictionary<string, string>();

6. Methods in Dictionaries

7. Remove element:
Dict.Remove(“Compact");
Add element:
Dict.Add(“Compact", 21);
Methods in C# Dictionaries
In C#, A dictionary can provide methods like:
Find element:
if (!Dict.ContainsKey(“Compact")) {
Dict[“Compact"] = 20;
}
Replace element:
Dict[“Compact"] = 8;

8. What are C# Hash-tables?

9. What are Hash-tables?
KEY VALUE
1 11
2 22
3 33
4 44
Each DictionaryEntry object in the collection has
two properties: a key and a value.
A Hash-Table can't have duplicate entries because
it's immutable.
In C#, a Hash-table stores (Keys, Values) pairs,
where Keys can locate the storage.
The table's values can only be accessed by
defining key object.
Syntax:
Hashtable HT = new Hashtable();

10. Properties of C# Hash-table

11. Properties of C# Hash-table
Comparer: Returns or sets the IComparer to be
used.
KEY VALUE
1 11
2 22
3 33
4 44
Count: Gets the number of key/value pairs
contained in the hash table.
IsReadOnly: Returns a value indicating if the hash
table is a read-only hash table.
Item: Returns or sets the value corresponding to
the provided Key.
Keys: Returns an ICollection holding the hash
table's keys.
Values: Returns an ICollection holding the hash
table's values.

12. Methods in C# Hash-table

13. Methods in C# Hash-table
Various methods in a hash table are:
Add: Inserts an element in the hash table with the
provided key and value.
KEY VALUE
1 11
2 22
3 33
4 44
Clear: Clears the hash table of all its elements.
ContainsKey: Indicates whether or not the hash table
contains the supplied key.
ContainsValue: Indicates whether or not the hash
table contains the specified value.

14. C# Hash-sets

15. C# Hash-sets
Sets in C# are called HashSet.
HashSet in C# makes sure there aren't any duplicate
strings or elements in an array.
Value ‘John’ ‘Mary’ ‘Eddie’ ‘Tony’ ‘Snow’ ‘Ray’
Syntax:
var h = new HashSet<string>(arr1);

16. Implementation