Working with Strings in C#: A Comprehensive Guide to String Manipulation

Master string manipulation in C#. This tutorial covers string creation, immutability, and explores a wide range of built-in methods for string operations (concatenation, comparison, substring extraction, etc.), providing a comprehensive guide to efficient string handling in C#.

Working with Strings in C#

Understanding C# Strings

In C#, a string is an object of the `System.String` class. It represents a sequence of characters. Strings are immutable; once created, their value cannot be changed (any operation that appears to modify a string actually creates a new string object). C# provides a rich set of built-in methods for manipulating strings, covering tasks such as concatenation, comparison, substring extraction, searching, trimming, and more. The `string` keyword is an alias for `System.String`, so both can be used interchangeably.

Creating Strings in C#

You can create strings using string literals or the `String` constructor. String literals are enclosed in double quotes (" ").

Example String Creation

string str1 = "Hello"; //String literal
string str2 = new string(new char[] { 'W', 'o', 'r', 'l', 'd' }); //String constructor

Common C# String Methods

C# provides a wide array of built-in methods for string manipulation. Here's a summary; each method would link to more detailed information in a full tutorial.

Method	Description
`Clone()`	Creates a shallow copy of the string.
`Compare()`	Compares two strings.
`CompareOrdinal()`	Compares two strings based on their numeric values.
`CompareTo()`	Compares this string to another string.
`Concat()`	Concatenates two or more strings.
`Contains()`	Checks if a string contains a specific substring.
`Copy()`	Creates a new string with the same value.
`CopyTo()`	Copies a portion of the string to a character array.
`EndsWith()`	Checks if the string ends with a specific substring.
`Equals()`	Compares two strings for equality.
`Format()`	Creates a formatted string.
`GetEnumerator()`	Returns an enumerator to iterate through the characters.
`GetHashCode()`	Returns a hash code for the string.
`GetType()`	Gets the type of the object (System.String).
`GetTypeCode()`	Gets the TypeCode for the string.
`IndexOf()`	Finds the index of the first occurrence of a specified substring.
`Insert()`	Inserts a substring at a specified index.
`Intern()`	Retrieves a reference to a string from the string pool.
`IsInterned()`	Checks if a string is interned.
`IsNormalized()`	Checks if the string is in Unicode normalization form C.
`IsNullOrEmpty()`	Checks if a string is null or empty.
`IsNullOrWhiteSpace()`	Checks if a string is null, empty, or whitespace.
`Join()`	Concatenates an array of strings with a specified separator.
`LastIndexOf()`	Finds the last occurrence of a specified character.
`LastIndexOfAny()`	Finds the last occurrence of any character from an array.
`Normalize()`	Returns a normalized version of the string (Unicode normalization).
`PadLeft()`	Pads a string on the left with spaces or a specified character.
`PadRight()`	Pads a string on the right with spaces or a specified character.
`Remove()`	Removes characters from a string.
`Replace()`	Replaces occurrences of a substring with another substring.
`Split()`	Splits the string into an array of substrings.
`StartsWith()`	Checks if the string starts with a specific substring.
`Substring()`	Extracts a substring.
`ToCharArray()`	Copies the string to a character array.
`ToLower()`	Converts the string to lowercase.
`ToLowerInvariant()`	Converts the string to lowercase using invariant culture rules.
`ToString()`	Returns a string representation of the string (the string itself).
`ToUpper()`	Converts the string to uppercase.
`ToUpperInvariant()`	Converts the string to uppercase using invariant culture rules.
`Trim()`	Removes leading and trailing whitespace.
`TrimEnd()`	Removes trailing characters.
`TrimStart()`	Removes leading characters.

Conclusion

The `System.String` class in C# offers a vast array of methods for manipulating strings. Understanding these methods is essential for efficient string handling in C# applications.