C sharp string length

String. Length Свойство

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Возвращает число знаков в текущем объекте String.

public: property int Length < int get(); >;

Public ReadOnly Property Length As Integer

Значение свойства

Количество знаков в текущей строке.

Примеры

В следующем примере показано Length свойство .

// Sample for String::Length using namespace System; int main() < String^ str = "abcdefg"; Console::WriteLine( "1) The length of '' is ", str, str->Length ); Console::WriteLine( "2) The length of '' is ", "xyz", ((String^)"xyz")->Length ); int length = str->Length; Console::WriteLine( "1) The length of '' is ", str, length ); > /* This example displays the following output: 1) The length of 'abcdefg' is 7 2) The length of 'xyz' is 3 3) The length of 'abcdefg' is 7 */ 

string str = "abcdefg"; Console.WriteLine("1) The length of '' is ", str, str.Length); Console.WriteLine("2) The length of '' is ", "xyz", "xyz".Length); int length = str.Length; Console.WriteLine("3) The length of '' is ", str, length); // This example displays the following output: // 1) The length of 'abcdefg' is 7 // 2) The length of 'xyz' is 3 // 3) The length of 'abcdefg' is 7 

let str = "abcdefg" printfn $"1) The length of '' is " printfn $"""2) The length of '' is """ let length = str.Length printfn $"3) The length of '' is " // This example displays the following output: // 1) The length of 'abcdefg' is 7 // 2) The length of 'xyz' is 3 // 3) The length of 'abcdefg' is 7 

Class Sample Public Shared Sub Main() Dim str As String = "abcdefg" Console.WriteLine("1) The length of '' is ", str, str.Length) Console.WriteLine("2) The length of '' is ", "xyz", "xyz".Length) Dim length As Integer = str.Length Console.WriteLine("1) The length of '' is ", str, length) End Sub End Class ' 'This example displays the following output: ' 1) The length of 'abcdefg' is 7 ' 2) The length of 'xyz' is 3 ' 3) The length of 'abcdefg' is 7 

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Свойство Length возвращает количество Char объектов в этом экземпляре, а не число символов Юникода. Причина в том, что символ Юникода может быть представлен несколькими Char. System.Globalization.StringInfo Используйте класс для работы с каждым символом Юникода вместо каждого Char.

В некоторых языках, таких как C и C++, символ NULL обозначает конец строки. В .NET символ null можно внедрить в строку. Если строка содержит один или несколько символов NULL, они включаются в длину строки итогов. Например, в следующей строке подстроки «abc» и «def» разделяются символом NULL. Свойство Length возвращает значение 7, указывающее, что оно включает шесть букв, а также пустой символ.

using namespace System; using namespace System::Text; void main() < String^ characters = "abc" + L'0' + "def"; Console::WriteLine(characters->Length); // Displays 7 > 

string characters = "abc\u0000def"; Console.WriteLine(characters.Length); // Displays 7 

let characters = "abc\u0000def" printfn $"" // Displays 7 

Imports System.Text Module Example Public Sub Main() Dim characters As String = "abc" + ChrW(0) + "def" Console.WriteLine(characters.Length) ' Displays 7 End Sub End Module 

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String. Length Property

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Gets the number of characters in the current String object.

public: property int Length < int get(); >;

Public ReadOnly Property Length As Integer

Property Value

The number of characters in the current string.

Examples

The following example demonstrates the Length property.

// Sample for String::Length using namespace System; int main() < String^ str = "abcdefg"; Console::WriteLine( "1) The length of '' is ", str, str->Length ); Console::WriteLine( "2) The length of '' is ", "xyz", ((String^)"xyz")->Length ); int length = str->Length; Console::WriteLine( "1) The length of '' is ", str, length ); > /* This example displays the following output: 1) The length of 'abcdefg' is 7 2) The length of 'xyz' is 3 3) The length of 'abcdefg' is 7 */ 

string str = "abcdefg"; Console.WriteLine("1) The length of '' is ", str, str.Length); Console.WriteLine("2) The length of '' is ", "xyz", "xyz".Length); int length = str.Length; Console.WriteLine("3) The length of '' is ", str, length); // This example displays the following output: // 1) The length of 'abcdefg' is 7 // 2) The length of 'xyz' is 3 // 3) The length of 'abcdefg' is 7 

let str = "abcdefg" printfn $"1) The length of '' is " printfn $"""2) The length of '' is """ let length = str.Length printfn $"3) The length of '' is " // This example displays the following output: // 1) The length of 'abcdefg' is 7 // 2) The length of 'xyz' is 3 // 3) The length of 'abcdefg' is 7 

Class Sample Public Shared Sub Main() Dim str As String = "abcdefg" Console.WriteLine("1) The length of '' is ", str, str.Length) Console.WriteLine("2) The length of '' is ", "xyz", "xyz".Length) Dim length As Integer = str.Length Console.WriteLine("1) The length of '' is ", str, length) End Sub End Class ' 'This example displays the following output: ' 1) The length of 'abcdefg' is 7 ' 2) The length of 'xyz' is 3 ' 3) The length of 'abcdefg' is 7 

Remarks

The Length property returns the number of Char objects in this instance, not the number of Unicode characters. The reason is that a Unicode character might be represented by more than one Char. Use the System.Globalization.StringInfo class to work with each Unicode character instead of each Char.

In some languages, such as C and C++, a null character indicates the end of a string. In .NET, a null character can be embedded in a string. When a string includes one or more null characters, they are included in the length of the total string. For example, in the following string, the substrings «abc» and «def» are separated by a null character. The Length property returns 7, which indicates that it includes the six alphabetic characters as well as the null character.

using namespace System; using namespace System::Text; void main() < String^ characters = "abc" + L'0' + "def"; Console::WriteLine(characters->Length); // Displays 7 > 

string characters = "abc\u0000def"; Console.WriteLine(characters.Length); // Displays 7 

let characters = "abc\u0000def" printfn $"" // Displays 7 

Imports System.Text Module Example Public Sub Main() Dim characters As String = "abc" + ChrW(0) + "def" Console.WriteLine(characters.Length) ' Displays 7 End Sub End Module 

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C# String Length: How to use it?

To get the string length in C#, use the .Length property.

string c = "Hello World!"; int stringLength = c.Length; // 12 characters in string Hello World!

Examples

using System; public class Program  public static void Main()  Console.WriteLine("Hello World".Length); // 11 string unicode = "\u1F642"; // represents 🙂 Console.WriteLine(unicode.Length); // 2 string str = ""; Console.WriteLine(str.Length); // 0 Console.WriteLine(string.Empty.Length); // 0 > >

What is String Length in C#?

String Length in C# is a property on the String object that returns the number of characters in a string. The returned length value is of type Int32.

The Length property of a string is the number of Char objects it contains, not the number of Unicode characters.

The length property returns the number of Char objects instead of the number of Unicode characters because a Unicode character might be represented by more than one character.

What is the max string length in C#?

The maximum string length in C# is 2^31 characters. That’s because String.Length is a 32-bit integer.

How to change string length in C#?

You can’t change the string length in C#. The String.Length property is read-only.

To change the string length, you need to create a new string.

If you try to change the Length property, you will get an error:

 error CS0200: Property or indexer 'string.Length' cannot be assigned to -- it is read only 

How to access each Unicode character?

To access each Unicode character in a C# string, you use the System.Globalization.StringInfo class to work with each Unicode character instead of each character.

Exception

One of the most frequent null-reference exceptions is with String.Length property.

If you try to access the Length property on a null string, you will get a NullReferenceException.

Many developers forget to check for null before accessing the Length property.

Index vs Length

In C#, string length returns the number of characters in a string.

The index property returns the zero-based position of the character that is located at a specified location within an instance of String.

The length property doesn’t start at 0. It starts at the first character in the string. But the index property starts at 0.

string test = "12345"; Console.WriteLine(test.IndexOf("1")); // 0

Under the hood

Internally, C# stores strings as a read-only collection of Char objects. There’s also a null-terminating character at the end of a C# string.

C# doesn’t count the null-terminating character in the length of a string. The null-character is just a way C# marks the end of a string under the hood.

Termination

Programming languages have different approaches to determine the string end:

• Null-terminated — Strings in C are null-terminated sequences of characters, with a special character following the last character—written «\0» — to show the end of the string.
• Length-prefixed -Pascal stores the length in the first bytes of the string.
• Length-and-Character Array — String as a structure with an array of characters, and stores the length in a separate allocation.

Changes in length

Programming languages have different approaches to handle changes in string length:

• Static string length is fixed and cannot be changed at runtime.
• Limited Dynamic string length can be increased or decreased, but the number of characters that can be stored in it is limited.
• Dynamic string length can grow or shrink as needed, up to the maximum size allowed by the underlying system.

In C#, strings have dynamic string length. It means that the string can grow or shrink as needed.

String class

The String class holds the implementation details and the string manipulation functionality. Looking at the source code, we can see that the string length is crucial for the string class.

Functionality such as String.Substring, String.IndexOf, and String.Remove require the length of a string in order to work correctly.

Josip Miskovic is a software developer at Americaneagle.com. Josip has 10+ years in experience in developing web applications, mobile apps, and games.

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