CODEWITHSUNDEEP
c#
Siddiqui
Siddiqui

Reputation: 7840

Dynamic array in C#

Is there any method for creating a dynamic array in C#?

Upvotes: 144

Views: 732124

Answers (9)

adnan Alyaari
adnan Alyaari

Reputation: 61

you can use arraylist object from collections class

using System.Collections;

static void Main()
{
  ArrayList arr = new ArrayList();
}

when you want to add elements you can use

arr.Add();

Upvotes: 2

Mehdi LAMRANI
Mehdi LAMRANI

Reputation: 11597

Sometimes plain arrays are preferred to Generic Lists, since they are more convenient (Better performance for costly computation -Numerical Algebra Applications for example, or for exchanging Data with Statistics software like R or Matlab)

In this case you may use the ToArray() method after initiating your List dynamically 

List<string> list = new List<string>();
list.Add("one");
list.Add("two");
list.Add("three");

string[] array = list.ToArray();

Of course, this has sense only if the size of the array is never known nor fixed ex-ante. if you already know the size of your array at some point of the program it is better to initiate it as a fixed length array. (If you retrieve data from a ResultSet for example, you could count its size and initiate an array of that size, dynamically)

Upvotes: 72

Avner
Avner

Reputation: 4556

You can do this with dynamic objects:

var dynamicKeyValueArray = new[] { new {Key = "K1", Value = 10}, new {Key = "K2", Value = 5} };

foreach(var keyvalue in dynamicKeyValueArray)
{
    Console.Log(keyvalue.Key);
    Console.Log(keyvalue.Value);
}

Upvotes: 6

sydur.rahman21
sydur.rahman21

Reputation: 175

Dynamic Array Example:

Console.WriteLine("Define Array Size? ");
int number = Convert.ToInt32(Console.ReadLine());

Console.WriteLine("Enter numbers:\n");
int[] arr = new int[number];

for (int i = 0; i < number; i++)
{
    arr[i] = Convert.ToInt32(Console.ReadLine());
}
for (int i = 0; i < arr.Length; i++ )
{
    Console.WriteLine("Array Index: "+i + " AND Array Item: " + arr[i].ToString());
}
Console.ReadKey();

Upvotes: -1

Luke T O&#39;Brien
Luke T O&#39;Brien

Reputation: 2835

This answer seems to be the answer you are looking for Why can't I do this: dynamic x = new ExpandoObject { Foo = 12, Bar = "twelve" }

Read about the ExpandoObject here https://msdn.microsoft.com/en-us/library/system.dynamic.expandoobject(v=vs.110).aspx

And the dynamic type here https://msdn.microsoft.com/en-GB/library/dd264736.aspx

Upvotes: 0

Shubham Gupta
Shubham Gupta

Reputation: 27

Use the array list which is actually implement array. It takes initially array of size 4 and when it gets full, a new array is created with its double size and the data of first array get copied into second array, now the new item is inserted into new array. Also the name of second array creates an alias of first so that it can be accessed by the same name as previous and the first array gets disposed

Upvotes: 1

Chris Van Opstal
Chris Van Opstal

Reputation: 37537

Take a look at Generic Lists.

Upvotes: 163

JaredPar
JaredPar

Reputation: 754525

Expanding on Chris and Migol`s answer with a code sample.

Using an array

Student[] array = new Student[2];
array[0] = new Student("bob");
array[1] = new Student("joe");

Using a generic list. Under the hood the List<T> class uses an array for storage but does so in a fashion that allows it to grow effeciently. 

List<Student> list = new List<Student>();
list.Add(new Student("bob"));
list.Add(new Student("joe"));
Student joe = list[1];

Upvotes: 105

Migol
Migol

Reputation: 8448

List<T> for strongly typed one, or ArrayList if you have .NET 1.1 or love to cast variables.

Upvotes: 37

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