C# Strings

In C# programming, a string is an instance of the System.String class representing a series of characters. Enclosed in double quotes, a string variable stores a character sequence and is declared using the string keyword. Various string operations like merging, comparing, extracting substrings, searching, trimming, replacing, etc., can be carried out. Strings are frequently employed in tasks related to processing text, receiving user input, handling file operations, and formatting data.

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For instance, when we compose a text on our mobile device, like "Greetings, John", the device stores this information internally as a string. Likewise, an email identifier such as john@gmail.com is also considered a string since it consists of a sequence of characters.

Syntax:

It has the following syntax.

string variableName = "Your text here";

In this particular syntax,

• ✅ String: This keyword is utilized to declare the string variable.
• ✅ VariableName: The name of the variable defines this.

Declaring and Initializing a String in C#

There are multiple methods to declare and set the initial value for a string variable in C# .

Declaration without initialization

If we intend to define a string utilizing simple and System.String, we can employ the subsequent syntax:

string myString1;

// Declaration using System.String.

System.String myString2;

Initializing with a string literal

To assign a string with a string literal at the initialization stage, we can employ the subsequent syntax:

string myString3 = "Welcome to C# Programming tech";

String Initialization using Local Variables

By utilizing the var keyword, we have the capability to generate a string with implicit typing.

var localString = "Still a strongly-typed string.";

String Initialization using a Constructor

In C#, a string constructor can generate a string from a char, char, or sbyte.

char [] source = {'X', 'Y', 'Z'};

string myString4 = new string (source);

C# Simple String Example

Let's consider an example to demonstrate string manipulation in C#.

Example

using System;  

public class StringExample  

{  

    public static void Main(string[] args)  

    {  

        string s1 = "hello";  

  

        char[] ch = { 'c', 's', 'h', 'a', 'r', 'p' };  

        string s2 = new string(ch);  

         

        Console.WriteLine(s1);  

        Console.WriteLine(s2);  

    }  

}

Output:

hello

csharp

Explanation:

In this instance, we explore two methods of string creation in C#. Initially, the string s1 is formed through a string literal, whereas the string s2 is generated from a character array by employing the new string constructor. Ultimately, we display the outcomes of both strings: "hello" and "csharp".

Characteristics of Strings

There are several characteristics of strings in C#. Some of them are as follows.

• ✅ Immutable: In the C# programming language, strings are immutable, which means that they can't be modified after creation.
• ✅ Reference Type: Strings are a reference type, but they act as a value type in some scenarios.
• ✅ Unicode Support: Strings have Unicode characters, which allows support for multiple languages.
• ✅ Null and Embedded Null: Strings can be null, which means that it doesn't represent any value, or they can contain an embedded null character (\0).
• ✅ Operator Overloading: Strings support the operator overloading, such as (+) for concatenation and (==) for comparison.

C# String Class

In the C# programming language, the String class is an intrinsic class that signifies a sequence of characters. It is contained within the System.namespace and functions as a reference type. This class offers a range of attributes and functions for effectively generating, modifying, and comparing strings.

C# String Methods

The table below illustrates various kinds of functions in the C# programming language.

C# String Method Example

Let's consider an example to demonstrate the string method in the C# programming syntax.

Example

using System;

class C# Tutorial {

    public static void Main() {

        // Creating strings

        string city = "Delhi";

        string country = "India";

        // Using ToUpper and ToLower methods

        Console.WriteLine("Uppercase: " + city.ToUpper());

        Console.WriteLine("Lowercase: " + city.ToLower());

        // Using the Trim method

        string sp = "Welcome to C# Programming tech";

        Console.WriteLine("Trimmed: " + sp.Trim() );

        // Using the Replace method

        string rep = country.Replace("India", "Bharat");

        Console.WriteLine("Replaced String: " + rep); 

        // Using the Split method

        string fruits ="Apple,Banana,Cherry";

        string [] fruitArray = fruits.Split(',');

        Console.WriteLine("Fruits after split: ");

        foreach (string f in fruitArray) {

            Console.WriteLine(f);

        }

        // Using StartsWith and EndsWith methods

       Console.WriteLine("Does the city start with 'Del'?" + city.StartsWith("Del"));

   Console.WriteLine("Does the country end with 'dia'?" + country.EndsWith("dia"));

        // Using the IndexOf method

        int index = fruits.IndexOf("Banana");

        Console.WriteLine("Index of Banana: " + index);

        // Using String Copy method

        string copyCity = String.Copy(city);

        Console.WriteLine("Copied String: " + copyCity);

        // Using Null or Empty Check method

        string emptyStr = "";

        Console.WriteLine("Is emptyStr null or empty?" + String.IsNullOrEmpty(emptyStr));

    }

}

Output:

Uppercase: DELHI

Lowercase: delhi

Trimmed: Welcome to C# Programming tech

Replaced String: Bharat

Fruits after split: 

Apple

Banana

Cherry

Does the city start with 'Del'?True

Does the country end with 'dia'?True

Index of Banana: 6

Copied String: Delhi

Is emptyStr null or empty?True

Explanation:

In this instance, we showcase the application of different string techniques in C#. Initially, we apply the conversion functions like ToUpper and ToLower. The trim function eliminates surplus spaces, and the Replace function substitutes a segment of a string. Subsequently, the split function disintegrates the string into an array.

Afterward, the StartsWith function examines beginnings and the EndWith function inspects endings. The IndexOf technique locates where a substring appears within a string. String.Copy is employed to duplicate an existing string, while String.IsNullorEmpty is utilized to verify if a string is either null or empty.

String Literals

C# has three different types of string literals. These are as follows:

• ✅ Quoted String Literals
• ✅ Verbatim Literals
• ✅ Raw String Literals

Next, we will explore each of these text constants individually in C#.

1) Quoted String Literals

In C# programming, quoted string literals are enclosed within double quote characters (") and typically appear on a single line. These literals allow for the utilization of escape sequences to represent special characters such as newline (\n), tab (\t), double quote (\") and backslash (\).

string text1 = " Learning C# is fun and interesting. ";

string text2 = " This sentence\r\n has a line break. ";

/* The resulting string:

This sentence

has a line break.

*/

Numerous escape sequences are employed within string literals.

2) Verbatim String Literals

In C#, a verbatim string literal is employed to generate multi-line strings. Utilizing verbatim strings enables the inclusion of special characters and line breaks within the string content. To create a verbatim string, simply prefix the string with the @ symbol before the opening double quotes.

For Example:

string str1 = @" spdf

abc ";

string str2 = @" \mypcsharedproject ";

string str3 = @" xyz@gmail.com ";

3) Raw String Literals

In C#, a verbatim string literal preserves whitespaces, line breaks, and special characters, enabling the breaking of embedded lines. It employs triple quotes (""") to denote the string literals. These literals can encompass any characters without the need for escape sequences, maintaining the exact appearance of the string in the code storage or display.

String Concatenation

In C#, the process of combining String values is done through the (+) operator. This operator enables the merging of two strings into a unified format. Alternately, String.Concat or String.Join methods can also be employed for string concatenation.

C# String Concatenation Example

Let's consider a scenario to demonstrate how strings can be combined in C#.

Example

using System;

class TPT {

    public static void Main() {

        // Declaration of string variables

        string fname = "Hello World";

        string lname = " Tech";

        // using + operator

        string fullName = fname + " " + lname;

        // Displaying the result

        Console.WriteLine("Full Name: " + fullName);

    }

}

Output:

Full Name: C# Tutorial

Explanation:

In this instance, we define a class named TPT and specify string variables within it. Following the initialization of these variables, we employ the (+) operator to combine the string values. Finally, the Console.WriteLine method is utilized to display the resulting output.

String Interpolation

In C#, utilizing string interpolation proves to be a powerful method for string concatenation. This approach enables the direct embedding of variables within a string, thereby enhancing code readability.

C# String Interpolation Example

Let's consider an example to demonstrate string interpolation in C#.

Example

using System;

class TPT

{

    public static void Main()

    {

        string fName = "Welcome to";

        string lName = "C# Tutorial";

        int age = 24;

        // Using string interpolation

        string msg = $"Hello, {fName}{lName} and I am {age} years old.";

        Console.WriteLine(msg);

    }

}

Output:

Hello, Welcome to C# Programming tech and I am 24 years old.

Explanation:

In this illustration, we showcase the application of string interpolation in C#. Initially, we declare three variables: fName, lName, and age, to hold segments of a message and an integer. Subsequently, we employ interpolation by adding a $ sign before the string. This feature enables the formation of a clear and brief message within the msg variable.

Finding the length of a string in C#

Let's consider an example to determine the string's size by utilizing the length property in C#.

Example

using System;

class TPT

{

    public static void Main()

    {

        // Declaration of a string

        string msg = "Welcome to C# Programming tech";

        // using the length property

        int l = msg.Length;

        Console.WriteLine($"The string is: {msg}");

        Console.WriteLine($"The length of the string: {l}");

    }

}

Output:

The string is: Welcome to C# Programming tech

The length of the string: 22

Explanation:

In this instance, we define a class called TPT and establish a string variable named msg. Following the initialization of the value, we employ the Length property to determine the string's character count.

Comparing String

In C# coding language, strings can undergo a comparison through methods like String.Compare, Equals, and == operator. The outcome of this comparison is an integer value indicating if a string is less than, equal to, or greater than another string.

C# String Example to Compare Two Strings

Let's consider a scenario to demonstrate the various techniques for comparing two strings in C#.

Example

using System;

public class StringCompareExample

{

    public static void Main()

    {

        string str1 = "Csharp";

        string str2 = "Java";

        // Using String.Compare()

        int result = String.Compare(str1, str2);

        // Using Equals()

        bool isEqual = str1.Equals(str2);

        // Using ==

        bool equalOperator = (str1 == str2);

        Console.WriteLine("String.Compare() Result: " + result);

        Console.WriteLine("Equals() Result: " + isEqual);

        Console.WriteLine("== Operator Result: " + equalOperator);

    }

}

Output:

String.Compare() Result: -1

Equals() Result: False

== Operator Result: False

Explanation:

In this illustration, we showcase the comparison of strings using various techniques in C#. In this scenario, the function string.Compare yields a result of -1 as "Csharp" precedes "Java" in alphabetical order. The methods Equals and == both yield False outcomes since the strings are not identical.

Conclusion

In summary, a C# string is a series of characters that serves as a representation of textual information. Strings play a crucial role in programming for the storage and manipulation of textual data like words and sentences. They offer various predefined functions that simplify tasks like combining, altering, comparing, removing whitespace, and searching. Utilizing strings is essential for developing well-structured, optimized, and comprehensible software.

C# String FAQs

1) Define a string in C#?

In C#, a string refers to an instance of the System.String class, serving as a collection of characters. Enclosed within double quotes, a string variable contains a series of characters and is declared using the string keyword.

2) How can we compare two strings in C#?

In C#, strings can be compared using the String.Compare, Equals, and == operator. The String.Compare method returns an integer value that represents whether one string is less than, equal to, or greater than another string.

• ✅ If the result is 0, both strings are equal.
• ✅ If the result is less than 0, the first string is smaller.
• ✅ If the result is greater than 0, the first string is larger.

3) Why does a string immutable in C#?

In C#, a string is immutable, indicating that its value cannot be modified after initialization.

4) What is a string concatenation in C#?

In C#, a String is combined using the (+) operator, enabling the merging of two string values into a unified format.

string greet = "Welcome" + " to" + "C# Tutorial";

5) What is string interpolation in C#?

String interpolation stands out as the optimal method for merging strings. This technique enables the direct inclusion of variables within a string, thereby enhancing code readability.

string name = "John";

string message = $"Hello, {name}!";