C# declare empty string array

Question

I need to declare an empty string array and i'm using this code

string[] arr = new String[0]();

But I get "method name expected" error.

What's wrong?

@James - maybe there is a more elegant way to do whatever he is trying to do. — Mr T.
– Mr T., Commented May 30, 2013 at 10:59
@aquanat - although an answer has already been accepted and i don't know your code or the logic behind it, i would humbly suggest you not to return an empty array but null and check from the calling function if the returned value is null or not. I think that it would be much more elegant, readable and efficient. — Mr T.
– Mr T., Commented May 30, 2013 at 12:07
The reason you would not want to return null is that the consumer of the method has to check for null. For instance, the consumer of the method could put the returned value in a foreach and if an empty array is returned, there is no problem. However, if null is returned, there has to be a check for null before iterating the returned value — JAB
– JAB, Commented Nov 18, 2014 at 17:56

Atish Kumar Dipongkor · Accepted Answer · 2013-12-12 09:07:39Z

350

Try this

string[] arr = new string[] {};

edited Dec 12, 2013 at 9:07

answered May 30, 2013 at 10:59

Atish Kumar Dipongkor

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3 Comments

aquanat Over a year ago

Thanks everybody...don't ask me why, but the only way was: string[] arr = new String[0] as string[];

Joe Over a year ago

Atish's method worked and eliminated visual studio's complain about using a variable that is not initialized if I assign it in an if statement

Jannick Breunis Over a year ago

Other option is c# Array.Empty<string>()

Andrei · Accepted Answer · 2013-05-30 11:14:50Z

78

Your syntax is wrong:

string[] arr = new string[]{};

or

string[] arr = new string[0];

edited May 30, 2013 at 11:14

answered May 30, 2013 at 10:52

Andrei

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2 Comments

It'sNotALie. Over a year ago

Why is string both capitalized and not capitalized in you examples?

Andrei Over a year ago

@newStackExchangeInstance, just copied code "as is" from the question. Both lines compile fine, although I agree that following one style is better.

AminM · Accepted Answer · 2020-08-25 11:16:25Z

49

If you are using .NET Framework 4.6 and later, they have some new syntax you can use:

using System;  // To pick up definition of the Array class.

var myArray = Array.Empty<string>();

edited Aug 25, 2020 at 11:16

AminM

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answered Nov 1, 2016 at 19:48

Brian

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1 Comment

ZunTzu Over a year ago

Nice trick! And it also works with IList<T> : IList<string> x = Array.Empty<string>();

Bharadwaj · Accepted Answer · 2013-05-30 10:55:11Z

9

You can try this

string[] arr = {};

answered May 30, 2013 at 10:55

Bharadwaj

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1 Comment

xr280xr Over a year ago

This is, surprisingly, resulting in null for me when using within an object initializer.

Rahul · Accepted Answer · 2013-05-30 10:59:07Z

9

Arrays' constructors are different. Here are some ways to make an empty string array:

var arr = new string[0];
var arr = new string[]{};
var arr = Enumerable.Empty<string>().ToArray()

(sorry, on mobile)

edited May 30, 2013 at 10:59

Rahul

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answered May 30, 2013 at 10:56

It'sNotALie.

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Comments

OrionMD · Accepted Answer · 2018-05-23 10:18:45Z

2

Your syntax is invalid.

string[] arr = new string[5];

That will create arr, a referenced array of strings, where all elements of this array are null. (Since strings are reference types)

This array contains the elements from arr[0] to arr[4]. The new operator is used to create the array and initialize the array elements to their default values. In this example, all the array elements are initialized to null.

Single-Dimensional Arrays (C# Programming Guide)

edited May 23, 2018 at 10:18

OrionMD

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answered May 30, 2013 at 10:53

Soner Gönül

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1 Comment

aquanat Over a year ago

Thanks everybody...don't ask me why, but the only way was: string[] arr = new String[0] as string[];

Rahul · Accepted Answer · 2013-05-30 11:00:15Z

0

If you must create an empty array you can do this:

string[] arr = new string[0];

If you don't know about the size then You may also use List<string> as well like

var valStrings = new List<string>();

// do stuff...

string[] arrStrings = valStrings.ToArray();

edited May 30, 2013 at 11:00

answered May 30, 2013 at 10:53

Rahul

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1 Comment

Soner Gönül Over a year ago

I'm so sorry. I accidentally ruined your post with wrong edits.

CodeCaster · Accepted Answer · 2013-05-30 11:32:26Z

0

Those curly things are sometimes hard to remember, that's why there's excellent documentation:

// Declare a single-dimensional array  
int[] array1 = new int[5];

edited May 30, 2013 at 11:32

answered May 30, 2013 at 10:54

CodeCaster

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1 Comment

CodeCaster Over a year ago

No need to edit this answer, as answers serve the gereral purpose, and not the specific question per say. It answers "What is the syntax to declare and initialize an array" and is a citation from the link I posted. OP can replace int with string if he likes.

Nwafor · Accepted Answer · 2023-10-25 07:51:43Z

0

// zero-element array
var arr0 = System.Array.Empty<string>(); // Recommended: https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/quality-rules/ca1825
var arr1 = new string[0];

// 5-Elements array with null values
var arr2 = new string[5];

// 5-Elements array with empty string values
var arr3 = System.Linq.Enumerable.Repeat(string.Empty, 5).ToArray();
var arr4 = System.Linq.Enumerable.Range(0, 5).Select(_ => string.Empty).ToArray();

answered Oct 25, 2023 at 7:51

Nwafor

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Comments

Martin · Accepted Answer · 2022-12-19 14:59:09Z

-2

could get something like this with: private List list = new List(); string[] dnormlines kist.ToArray();

answered Dec 19, 2022 at 14:59

Martin

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Comments

Philip John · Accepted Answer · 2018-03-26 12:38:18Z

-5

The following should work fine.

string[] arr = new string[] {""};

edited Mar 26, 2018 at 12:38

Philip John

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answered Mar 26, 2018 at 11:51

Karthikeyan Gunasheker

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2 Comments

Guillermo Prandi Over a year ago

That's not an empty array, as it contains one element which is an empty string. arr.Length() will return 1.

hubert17 Over a year ago

This may not be an empty array but I find this answer null safe. Thanks! 1 up!

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