String Class
// Represents an immutable sequence of characters.
The System.String class represents a text string. A string is a sequence of Unicode characters. Strings are ordered sequences of characters of a specified length. The value of a string is.
Summary
| Constructor | Description |
|---|---|
String(Char[]) |
Initializes a new instance of the String class by using an array of 16-bit Unicode characters. |
String(Char[], Int32, Int32) |
Initializes a new instance of the String class by using a subarray of 16-bit Unicode characters, a starting position, and a length. |
| Method | Description |
|---|---|
IsNullOrEmpty(String) |
Indicates whether the specified string is null or an Empty string. |
IsNullOrWhiteSpace(String) |
Indicates whether the specified string is null, empty, or consists only of white-space characters. |
Compare(String, String) |
Compares two strings using the conventions of the current culture. |
Concat(Object[]) |
Concatenates the string representations of the elements in a specified array of objects. |
EndsWith(String) |
Determines whether the end of this string instance matches the specified string. |
IndexOf(String) |
Reports the zero-based index of the first occurrence of a specified string within this instance. |
Insert(Int32, String) |
Inserts a specified string into this instance at a specified character position. |
Join(String, String[]) |
Concatenates the elements of a string array, using the specified separator between each element. |
Remove(Int32) |
Removes a specified number of characters from the current string beginning at a specified position. |
Replace(Char, Char) |
Replaces all occurrences of a specified Unicode character in this instance with another specified Unicode character. |
Split(Char[]) |
Splits a string into substrings based on specified delimiters. |
StartsWith(String) |
Determines whether the beginning of this string instance matches the specified string. |
Substring(Int32) |
Retrieves a substring from this instance. The substring starts at a specified character position and continues to the end of the string. |
ToLower() |
Converts this string to lowercase. |
ToUpper() |
Converts this string to uppercase. |
Trim() |
Removes all leading and trailing white space characters from the current String object. |
Remarks
Strings are immutable objects. This means that once a string object is created, its value cannot be changed. Methods that appear to modify a string, such as Replace or Substring, actually return a new string object whose value is the result of the operation.
Immutability Example
using System;
public class Example
{
public static void Main()
{
string original = "Hello";
string modified = original.Replace('l', 'x');
Console.WriteLine($"Original: {original}"); // Output: Original: Hello
Console.WriteLine($"Modified: {modified}"); // Output: Modified: Hexxo
}
}