String Methods and Tips for C# Developers

November 11, 2023 Reading time: 4min, 15sec

String Methods and Tips for C# Developers

String methods (operations) in C# form a fundamental component of any software application. In this article, we will explore essential string methods in the C# language and provide tips on their usage. This information will assist you in making your code more effective, readable, and performant.

Table of Contents

1. What is a String and How to Declare It?

In C#, a string is a data type representing textual data. To declare a string, you can start with the following example:

string myString = "Hello, World!";

This declaration creates a variable named myString and assigns the text “Hello, World!” to it.

2. Concat() Method: String Concatenation

To concatenate strings, you can use the Concat() method. For example:

string firstName = "John";
string lastName = "Doe";
string fullName = string.Concat(firstName, " ", lastName);

In this example, the fullName variable will be concatenated as “John Doe.”

3. Length Property: String Length

To determine the length of a string, use the Length property:

string myString = "This is an example sentence.";
int length = myString.Length;

In this case, the length variable will be set to 24.

4. ToUpper() and ToLower() Methods: Changing Case

To convert a string to uppercase or lowercase, use the ToUpper() and ToLower() methods:

string myString = "This is an example sentence.";
string upperCase = myString.ToUpper();
string lowerCase = myString.ToLower();

These methods will convert all letters to uppercase or lowercase, respectively.

5. IsNullOrEmpty() Method: Checking for Empty or Null Strings

string myString = "This is an example sentence.";
bool isNullOrEmpty = string.IsNullOrEmpty(myString);

This method checks whether a string is empty or null.

6. Replace() Method: Replacing a Specific Character or Substring

string originalString = "This is an example sentence.";
string replacedString = originalString.Replace("example", "great");

In this example, it replaces “example” with “great.”

7. Trim() Method: Removing Leading and Trailing Whitespace

string myString = "   This is an example sentence.   ";
string trimmedString = myString.Trim();

This example removes leading and trailing whitespace.

8. Compare() Method: String Comparison

string str1 = "abc";
string str2 = "ABC";
int comparisonResult = string.Compare(str1, str2, StringComparison.OrdinalIgnoreCase);

This example compares two strings without considering case sensitivity.

9. Substring() Method: Extracting a Substring by Count

string originalString = "This is an example sentence.";
string subStringByCount = originalString.Substring(3, 8);

This usage extracts a specified number of characters.

10. Format() Method: String Formatting

string formattedString = string.Format("My name is {0} and I am {1} years old.", "John", 30);

In this example, it replaces variables in the string.

11. IsInterned() Method: Checking if a String is Interned

string str1 = "abc";
string str2 = new string("abc".ToCharArray());
bool isInterned = string.IsInterned(str1) != null;

This method checks if a string is interned.

12. Copy() Method: Creating a New String with a Specific Character Count

string originalString = "This is an example sentence.";
char[] charArray = new char[10];
originalString.CopyTo(3, charArray, 0, 10);
string copiedString = new string(charArray);

This example creates a new string with a specific character count.

13. IsNormalized() Method: Checking Unicode Normalization

string unicodeString = "Cafe\u0301";
bool isNormalized = unicodeString.IsNormalized();

This method checks Unicode normalization.

14. ToCharArray() Method: Converting a String to a Character Array

string myString = "C# String Methods";
char[] charArray = myString.ToCharArray();

This example converts a string to a character array.

15. IndexOf() and LastIndexOf() Methods: Finding the Index of a Character or Substring

string myString = "C# Programming";
int indexOfA = myString.IndexOf('A');
int lastIndexOfA = myString.LastIndexOf('A');

This example finds the first and last index of a specific character.

16. ToArray() Method: Converting a String to a Character Array

string myString = "C# String Methods";
char[] charArray = myString.ToArray();

This example converts a string to a character array.

17. Split() Method: Splitting a String with a Specific Delimiter

string myString = "C#-Java-Python";
string[] languages = myString.Split('-');

This example splits the string with a specific delimiter and places it into an array.

18. PadLeft() and PadRight() Methods: Padding a String to a Specific Length

string myString = "123";
string paddedLeft = myString.PadLeft(5, '0');
string paddedRight = myString.PadRight(5, '0');

This example pads the string to a specific length, either on the left or right.

19. ToLowerInvariant() and ToUpperInvariant() Methods: Case Conversion (Invariant Culture)

string myString = "Hello, World!";
string lowerCaseInvariant = myString.ToLowerInvariant();
string upperCaseInvariant = myString.ToUpperInvariant();

These methods convert to lowercase or uppercase without considering culture.

20. StartsWith() and EndsWith() Methods: Checking if a String Starts or Ends with a Specific Substring

string myString = "C# Programming";
bool startsWithCSharp = myString.StartsWith("C#");
bool endsWithProgramming = myString.EndsWith("Programming");