YouTipCsharp Sortedlist
[ C# Collections](#)
In C#, a SortedList is a collection that automatically sorts elements by key. It stores data as key-value pairs and automatically sorts them in ascending order based on the key when adding or updating.
The SortedList class represents a collection of key-value pairs sorted by key. These pairs can be accessed by both key and index.
A SortedList is a combination of an array and a hash table. It contains a list of items that can be accessed using either a key or an index. If you access items by index, it acts like a dynamic array (ArrayList). If you access items by key, it acts like a hash table (Hashtable). The items in the collection are always sorted by key value.
There are two versions of SortedList:
1. **Non-generic `SortedList`** (`System.Collections.SortedList`)
2. **Generic `SortedList`** (`System.Collections.Generic.SortedList`)
**Features:**
* **Automatic Sorting**: All keys are sorted in ascending order without needing to manually call a sort method.
* **Key-Value Pair Storage**: Each key is unique, but the associated value can be duplicated.
* **Dynamic Capacity Adjustment**: Automatically adjusts the internal storage size as needed.
* **Index Access**: Data can be accessed via key or index.
* **Efficient Operations**: Average time complexity for retrieval, insertion, and deletion is O(log n).
The following table lists some common **properties** of the **SortedList** class:
| Property Name | Type | Description |
| --- | --- | --- |
| `Count` | `int` | Gets the number of key-value pairs in the sorted list. |
| `Capacity` | `int` | Gets or sets the capacity of the sorted list. |
| `Comparer` | `IComparer` or `IComparer` | Gets the comparer used to sort the keys. |
| `IsReadOnly` | `bool` | Indicates whether the sorted list is read-only. |
| `IsFixedSize` | `bool` | Indicates whether the sorted list has a fixed size (always `false`). |
| `Keys` | `ICollection` or `IList` | Gets all the keys in the sorted list. |
| `Values` | `ICollection` or `IList` | Gets all the values in the sorted list. |
The following table lists some common **methods** of the **SortedList** class:
| Method Name | Return Type | Description |
| --- | --- | --- |
| **Add & Remove** | | |
| `Add(TKey key, TValue value)` | `void` | Adds the specified key-value pair to the sorted list. |
| `Remove(TKey key)` | `bool` | Removes the element with the specified key from the sorted list. |
| `RemoveAt(int index)` | `void` | Removes the key-value pair at the specified index from the sorted list. |
| `Clear()` | `void` | Removes all elements from the sorted list. |
| **Find & Access** | | |
| `ContainsKey(TKey key)` | `bool` | Determines whether the sorted list contains the specified key. |
| `ContainsValue(TValue value)` | `bool` | Determines whether the sorted list contains the specified value. |
| `IndexOfKey(TKey key)` | `int` | Returns the index of the specified key. |
| `IndexOfValue(TValue value)` | `int` | Returns the index of the specified value. |
| `TryGetValue(TKey key, out TValue value)` | `bool` | Gets the value associated with the specified key, returning `true` if found. |
| **Copy & Enumerate** | | |
| `CopyTo(Array array, int index)` | `void` | Copies the elements of the sorted list to an array, starting at the specified index. |
| `GetEnumerator()` | `IEnumerator` | Returns an enumerator that iterates through the sorted list. |
The following examples demonstrate the concept of SortedList.
**Non-generic version operations:**
## Example
using System;
using System.Collections;
namespace CollectionsApplication
{
class Program
{
static void Main(string[] args)
{
SortedList sl =new SortedList();
sl.Add("001", "Zara Ali");
sl.Add("002", "Abida Rehman");
sl.Add("003", "Joe Holzner");
sl.Add("004", "Mausam Benazir Nur");
sl.Add("005", "M. Amlan");
sl.Add("006", "M. Arif");
sl.Add("007", "Ritesh Saikia");
if(sl.ContainsValue("Nuha Ali"))
{
Console.WriteLine("This student name is already in the list");
}
else
{
sl.Add("008", "Nuha Ali");
}
// Get the collection of keys
ICollection key = sl.Keys;
foreach(string k in key)
{
Console.WriteLine(k +": "+ sl);
}
}
}
}
When the above code is compiled and executed, it produces the following result:
001: Zara Ali002: Abida Rehman003: Joe Holzner004: Mausam Banazir Nur005: M. Amlan 006: M. Arif007: Ritesh Saikia008: Nuha Ali
**Generic version:**
## Example
using System;
using System.Collections.Generic;
class Program
{
static void Main()
{
// Create a generic SortedList
SortedList sortedList =new SortedList();
// Add key-value pairs
sortedList.Add(2, "Banana");
sortedList.Add(1, "Apple");
sortedList.Add(3, "Cherry");
// Automatically sorted by key
Console.WriteLine("SortedList contents:");
foreach(var kvp in sortedList)
{
Console.WriteLine($"Key: {kvp.Key}, Value: {kvp.Value}");
}
// Find and access
Console.WriteLine($"n Value for key 2: {sortedList}");// Output: Banana
// Remove an element
sortedList.Remove(1);
Console.WriteLine("n After removing key 1:");
foreach(var kvp in sortedList)
{
Console.WriteLine($"Key: {kvp.Key}, Value: {kvp.Value}");
}
// Check key and value
Console.WriteLine($"n Contains key 3: {sortedList.ContainsKey(3)}");// Output: True
Console.WriteLine($"Contains value 'Apple': {sortedList.ContainsValue("Apple")}");// Output: False
}
}
[ C# Collections](#)