C# string

In C#, a string is a sequence of Unicode characters. Strings are used to represent text and are one of the most commonly used data types in C#.

To declare a string variable, you can use the string keyword:

string myString;

To initialize a string with a value, you can use string literals:

string myString = "Hello, world!";

You can also use string interpolation to concatenate strings with values of other data types:

int myInt = 42;
string myString = $"The value of myInt is {myInt}";

In this example, the value of myInt is inserted into the string using the syntax {myInt} inside the string literal.

Strings in C# are immutable, which means that once a string is created, its contents cannot be changed. However, you can create new strings from existing strings using various string manipulation methods, such as Substring(), ToLower(), ToUpper(), Trim(), Replace(), and many others.

Here are some examples of string manipulation methods:

string myString = "   Hello, world!   ";
string trimmedString = myString.Trim(); // removes leading and trailing white space
string lowerString = myString.ToLower(); // converts all characters to lowercase
string upperString = myString.ToUpper(); // converts all characters to uppercase
string replacedString = myString.Replace("world", "everyone"); // replaces "world" with "everyone"
string substring = myString.Substring(7, 5); // extracts "world" from the string

In addition to the string data type, C# also provides a StringBuilder class that allows you to efficiently build strings by appending or inserting characters or other strings. This can be useful when you need to concatenate a large number of strings or perform frequent modifications to a string.